Height controlling apparatus

ABSTRACT

A height controlling apparatus for controlling at least one actual height as a relative position of (a) a body of a vehicle and (b) at least one wheel of the vehicle relative to each other, the apparatus including at least one height controlling actuator which changes the at least one actual height; and an actuator control device which controls the at least one height controlling actuator so that the at least one actual height approaches at least one target height. The actuator control device includes a possibility detecting device which detects, before an absolute value of a difference of the at least one target height and the at least one actual height exceeds a reference value, whether there is a possibility that an object may be present in a direction in which the body is moved to change the at least one actual height, and a movement restraining portion which controls, when the possibility detecting device detects that there is the possibility, the at least one height controlling actuator to restrain a movement of the body in the direction.

The present application is a divisional of U.S. application Ser. No.11/298,666 filed Dec. 12, 2005, which is based on Japanese PatentApplication No. 2004-381910 filed on Dec. 28, 2004, the contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a height controlling apparatus thatcontrols a height of a vehicle by operating one or more heightcontrolling actuators.

2. Discussion of Related Art

Patent Document 1 (Japanese Patent Application Publication No.11-190629) discloses a height controlling apparatus wherein, when adifference of a target height and an actual height of a vehicle isgreater than a reference value, an operation of a height controllingactuator is stopped. Patent Document 2 (Japanese Patent ApplicationPublication No. 2003-170721) discloses that when a difference of atarget height and an actual height of a vehicle is greater than areference value, the target height is increased. Patent Document 3(Japanese Patent Application Publication No. 5-193325) discloses the artof informing a driver of a state in which a height controlling operationis being performed. Patent Document 4 (Japanese Patent ApplicationPublication No. 1-233111) discloses that a height controlling actuatoris controlled according to information received from a portablecontroller.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide the art ofdetecting, at an early timing, that there is a possibility that anobject may be present in a direction of movement of a body of a vehicle,when a height controlling operation is performed.

The above object may be achieved according to any one of the followingmodes of the present invention in the form of a height controllingapparatus, each of which is numbered like the appended claims and maydepend from the other mode or modes, where appropriate, to indicate andclarify possible combinations of the corresponding technical features.It is, however, to be understood that the present invention is notlimited to the technical features or any combinations thereof that willbe described below for illustrative purposes only. It is to be furtherunderstood that a plurality of features included in any one of thefollowing modes of the invention are not necessarily providedaltogether, and that the invention may be embodied without at least oneof the features described with respect to the same mode.

(1) A height controlling apparatus for controlling at least one actualheight as at least one relative position of (a) a body of a vehicle and(b) at least one wheel of the vehicle relative to each other, theapparatus comprising

at least one height controlling actuator which changes said at least oneactual height; and

an actuator control device which controls said at least one heightcontrolling actuator so that said at least one actual height approachesat least one target height,

wherein the actuator control device includes

a possibility detecting device which detects, before an absolute valueof a difference of said at least one target height and said at least oneactual height exceeds a first reference value, whether there is apossibility that an object may be present in a direction in which thebody is moved to change said at least one actual height, and

a movement restraining portion which controls, when the possibilitydetecting device detects that there is said possibility, said at leastone height controlling actuator to restrain a movement of the body insaid direction.

In the present height controlling apparatus, the actuator control devicecontrols the at least one height controlling actuator so that the atleast one actual height approaches at least one target height. Thus, thebody of the vehicle is moved relative to the wheel thereof. However, thepossibility detecting device detects whether there is a possibility thatan object may be present in a direction of movement of the body. Whenthe possibility detecting device detects that there is the possibility,the movement restraining portion controls the at least one heightcontrolling actuator to restrain the movement of the body in thatdirection. More specifically described, the movement of the body in thatdirection is stopped, a speed of the movement of the body in thatdirection is decreased, the direction of the movement of the body isreversed, or the movement of the body in that direction is not started.For example, if, before a height controlling operation is started, thepossibility detecting device detects that there is a possibility that anobject may be present in a direction of movement of the body in theheight controlling operation, the operation can be avoided from beingstarted.

In the present mode (1), the possibility detecting device detects,before an absolute value of a difference of the at least one targetheight and the at least one actual height exceeds a reference value,whether there is a possibility that an object may be present. Therefore,the present height controlling apparatus can more quickly detect thatthere is a possibility that an object may be present in a direction ofmovement of the body, than the height controlling apparatus disclosed bythe above-indicated Patent Document 1. Therefore, the body and/or theobject can be effectively prevented from being damaged.

The above phrase of “detecting, before an absolute value of a differenceof the at least one target height and the at least one actual heightexceeds a reference value, whether there is a possibility that an objectmay be present” means—detecting whether there is a possibility that anobject may be present, before the possibility is detected based on thedifference of the at least one target height and the at least one actualheight as taught by the prior art—. Therefore, the reference value maybe one that is not actually used in the present height controllingapparatus.

The at least one height controlling actuator may be (i) a fluid-operatedheight controlling actuator including a fluid-flow controlling actuatorthat controls flows of a working fluid into, and out of, a fluid chamberprovided between the body and the wheel, or (ii) a mechanical heightcontrolling actuator including a drive device, such as an electricmotor, that operates a mechanical device for changing a distance betweenthe body and the wheel, i.e., a relative position of the two elementsrelative to each other. The working fluid used by the fluid-operatedheight controlling actuator may be either a gas or a liquid.

(2) The height controlling apparatus according to the mode (1), whereinthe possibility detecting device includes a near-object detectingportion which detects whether there is the object near to the vehicle,and wherein the movement restraining portion includes anear-object-detection-dependent actuator control portion which controls,when the near-object detecting portion detects that there is the objectnear to the vehicle, said at least one height controlling actuator torestrain the movement of the body in said direction.

In the present height controlling apparatus, if the near-objectdetecting portion detects that there is an object near to the vehicle,the possibility detecting device judges that there is a possibility thatan object may be present in a direction of movement of the body, and thenear-object-detection-dependent actuator control portion controls the atleast one height controlling actuator to restrain the movement of thebody in that direction. Thus, in the present height controllingapparatus, the possibility detecting device can judge whether there isthe possibility, not only before a height controlling operation isstarted but also during the height controlling operation.

The near-object detecting portion may be one including a getting-outdetecting device that detects whether a person has got out of thevehicle or whether there is a possibility that a person may get out ofthe vehicle. If a person gets out of the vehicle and remains around thevehicle, it can be judged that there is a possibility that the luggageof the person may be present in the direction of movement of thevehicle's body.

A fact that a person has got out of the vehicle may be detected bydetecting that a door of the vehicle has been changed from its closedstate to its opened state, that a door has been kept to its openedstate, or that the height of the vehicle has been increased; and a factthat there is a possibility that a person may get out of the vehicle maybe detected by detecting that a seat belt of the vehicle has beenunfastened, that a door lock has been unlocked, or that a seating sensorhas been changed from its ON state to its OFF state.

The object detected by the near-object detecting portion and the objectthat may be present in the direction of movement of the body may be thesame object, or may be different objects. In some cases, the near-objectdetecting portion may detect the same object as the object that may bepresent in the direction of movement of the body (e.g., it may detect afirst portion of the object other than a second portion thereof that maybe present in the direction of movement of the body); and in othercases, it may detect the object other than the object that may bepresent in the direction of movement of the body (e.g., it may detect anobject present in at least one predetermined area, described below; inthis case, the possibility detecting device may judge that there is apossibility that another object may be present in the direction ofmovement of the body).

(3) The height controlling apparatus according to the mode (2), whereinthe near-object detecting portion includes an object-in-area detectingportion which detects whether there is the object in at least one areapredetermined with respect to the vehicle.

In the present height controlling apparatus, the object-in-areadetecting portion detects whether there is the object in at least onearea predetermined with respect to the vehicle. For example, theobject-in-area detecting portion may be one including an emitter thatemits, e.g., a laser beam; a receiver that receives the laser beamreflected from an object; and a processing portion that detects, basedon the received laser beam, whether an object is present in thepredetermined area. A scope of a detection area in which theobject-in-area detecting portion can detect an object is defined by thenarrower one of a first area in which the emitter can emit the laserbeam and a second area in which the receiver can receive the reflectedlaser beam. However, the above-indicated predetermined area may be thesame as the detection area, or may be narrower than the detection area.It is desirable that the predetermined area be appropriate for theobject-in-area detecting portion to detect, when a height controllingoperation is performed, whether there is a possibility that an objectmay be present in a direction of movement of the body.

The emitter may be one that emits not the laser beam but a millimeterwave, or one that emits a supersonic wave. In addition, theobject-in-area detecting portion may be one including an image takingdevice that takes an image of the predetermined area and thereby detectsthe presence of an object.

The object-in-area detecting portion may be one that is exclusively usedfor the present height controlling apparatus. However, an element suchas a sensor that is employed by the vehicle for a different purpose maybe utilized as the object-in-area detecting portion. For example, atleast one of (a) clearance sonars that are provided in respectivecorners of the vehicle and each of which detects an object present in acorresponding one of predetermined areas around the corners; a back orrear sonar that is provided in a rear portion of the vehicle and detectsan object present in a predetermined area in rear of the vehicle; and afront-object detecting device that is provided in a front portion of thevehicle and is used in a cruising control.

(4) The height controlling apparatus according to the mode (3), whereinthe object-in-area detecting portion includes arelative-positional-relationship detecting portion which detects arelative-positional relationship between the body and the object presentin said at least one area.

The relative-positional relationship between the vehicle's body and theobject (more strictly described, the relative-positional relationshipbetween the object-in-area detecting portion (or therelative-positional-relationship detecting portion) and the object maybe a distance between the two elements; a direction of change of thedistance (i.e., whether the two elements are approaching each other, ormoving away from each other); an amount of change of the distance (i.e.,a relative-movement speed of the two elements relative to each other);or an acceleration of change of the distance (i.e., a relative-movementacceleration of the two elements relative to each other). Based on therelative-positional relationship between the vehicle's body and theobject, it is possible to detect a degree of possibility (i.e., aprobability) that the object may be present in a direction of movementof the body.

For example, it can be judged that the degree of possibility is high,when the distance between the body and the object present in thepredetermined area is small than when the distance is great (i.e., whenthe object is near to the body than when the object is distant from thebody).

In addition, it can be judged that the degree of possibility is high,when the distance decreases than when the distance increases.

(5) The height controlling apparatus according to the mode (3) or themode (4), wherein the object-in-area detecting portion includes anoperation detecting portion which detects whether an operation is beingperformed by an operator with respect to the vehicle.

In the present height controlling apparatus, the operation detectingportion detects, when an operator is performing a pre-selected sort ofoperation with respect to the vehicle, at least one action of a seriesof actions related to the pre-selected operation. The operationdetecting portion may be one that detects a proper action needed toachieve an aim (this action can be called a proper operation), one thatdetects a preparing action before the proper action (this action can becalled a preparing operation), or one that detects an ending actionafter the proper action (this action can be called an ending operation.

If a height controlling operation is stopped upon detection of thepre-selected operation, the operation can be effectively prevented frombeing adversely influenced by the changing of the vehicle's height.

(6) The height controlling apparatus according to the mode (5), whereinthe operation detecting portion detects at least one of an energy-sourcesupplying operation, an oil changing operation, a roof-carrier loadingoperation, a roof-carrier repairing operation, and a vehicle washingoperation.

The energy-source supplying operation may be an operation to supplygasoline to a vehicle having an engine as a drive source; or anoperation to electrically charge a battery of a vehicle having anelectric motor as a drive source, i.e., an operation to supply electricenergy to the vehicle. The gasoline supplying operation can be detectedby detecting whether a fuel lid opener motor is being operated, orwhether an open/close switch associated with a fuel lid opener is openedor closed, or detecting an amount of fuel present in a fuel tank.

The oil changing operation may be detected by detecting, with, e.g., aswitch, whether an inlet of an oil pan is in its opened state.

In a state in which a roof carrier of the vehicle is loaded withluggage, the vehicle's height (i.e., body height) decreases (i.e.,lowers). Thus, the roof-carrier loading operation may be detected basedon a body height detected by a body-height sensor. However, thevehicle's height changes when a person gets in, or out of, the vehicleor when a height controlling operation is performed. Therefore, when theroof-carrier loading operation is detected, it is desirable to take,into account, whether a person gets in, or out of, the vehicle and/orwhether a height controlling operation is performed. Alternatively, theroof-carrier loading operation may be detected by detecting, with atleast one open/close switch associated with at least one fixing jig ofthe roof carrier, whether the at least one fixing jig is operated.

During the vehicle washing operation, the temperature of an outersurface of the vehicle's body changes more largely, or more frequently,than the temperature of the environment, or changes to a different valuethan the temperature of ambient air. Therefore, the vehicle washingoperation may be detected based on the temperature of the body.Alternatively, the vehicle washing operation may be detected based on arain sensor that detects drops of rain.

When the energy-source supplying operation, the oil changing operation,or the vehicle washing operation is performed at, e.g., a known place,the operation may be detected based on information supplied from anavigation system. For example, when the vehicle is stopped at agasoline stand or an electric-power charging stand, the energy-sourcesupplying operation can be detected; and when vehicle is stopped at arepairing shop, the oil changing operation can be detected; and when thevehicle is stopped at a washing stand, the vehicle washing operation canbe detected.

(7) The height controlling apparatus according to any of the modes (3)through (6), wherein the object-in-area detecting portion includes aloaded-luggage detecting portion which detects whether the vehicle isloaded with a luggage.

The loaded-luggage detecting portion may detect whether the vehicle isloaded with luggage, based on, e.g., the body height detected by theabove-described body-height sensor, or based on whether aluggage-compartment door (i.e., an outer panel) is opened or closed.

(8) The height controlling apparatus according to any of the modes (3)through (7), wherein the object-in-area detecting portion includes adoor-state detecting portion which detects at least one of (a) whetherat least one door of the vehicle is opened and (b) whether at least onedoor of the vehicle is closed.

The door-state detecting portion may detect whether at least one door ofthe vehicle is opened or closed, based on, e.g., a detection signalsupplied from at least one door courtesy lamp switch. When the door ischanged from its closed state to its opened state, or when the door iskept to its opened state, it can be judged that there is a possibilitythat a person may be present around the vehicle and accordingly thatluggage may be present in a direction of movement of the body. In thismeaning, the door-state detecting portion can be called agetting-in-and-out detecting device that detects whether a person getsin, or out of, the vehicle.

(9) The height controlling apparatus according to any of the modes (1)through (8), wherein the possibility detecting device includes aheight-change-dependent possibility detecting portion which detectswhether there is said possibility, based on a change of said at leastone actual height, and wherein the movement restraining portion includesa height-change-dependent actuator control portion which controls, whenthe height-change-dependent possibility detecting portion detects thatthere is said possibility, said at least one height controlling actuatorto restrain the movement of the body in said direction.

In the present height controlling apparatus, the height-change-dependentpossibility detecting portion detects whether there is the possibility,based on a change of the at least one actual height of the vehicle.Therefore, the possibility can be detected at an earlier timing than thecase where the possibility is detected based on the at least one actualheight itself.

In the present height controlling apparatus, the possibility of presenceof object is detected after a height controlling operation is started,i.e., during the height controlling operation. As described above, acertain sort of operation may be detected based on the change of the atleast one actual height of the vehicle, as explained above.

(10) The height controlling apparatus according to the mode (9), whereinthe height-change-dependent possibility detecting portion includes achange-speed-related-amount-dependent possibility detecting portionwhich detects whether there is said possibility, based on a physicalamount related to a speed of change of said at least one actual height.

The physical amount related to the speed of change of the at least oneactual height may be the speed of change itself (i.e., an amount ofchange per unit time), or an n-time differentiated value (n≧1) of thespeed of change. A manner in which the body height is changed can beknown from a manner in which the height controlling actuator isoperated. Therefore, the change-speed-related-amount-dependentpossibility detecting portion can detect whether the change of theactual body height is abnormal, (i.e., whether there is a possibilitythat an object may be present in a direction of movement of the body),based on a nominal physical amount related to a nominal change speed ofthe body height, defined by the manner of operation of the heightcontrolling actuator, and an actual physical amount related to a changespeed of the actual body height.

Meanwhile, in many cases, the height controlling actuator is operated sothat the body height is changed at a constant speed. In those cases, itis effective to detect the possibility of presence of object, based onthe physical amount related to the change speed.

As far as the present specification is concerned, a change speed isexpressed as a positive value when it is actually changed in the samedirection as the direction in which it is to be changed by the operationof the height controlling actuator. Therefore, when the body height isdecreased, a direction in which the body approaches the wheel isexpressed as a positive direction; and when the body height isincreased, a direction in which the body moves away from the wheel isexpressed as a positive direction. On the other hand, in each case, achange acceleration is expressed as a positive value when the changespeed increases, and is expressed as a negative value when the changespeed decreases. That is, when the change speed of the body heightdecreases (i.e., when the body height decelerates), the changeacceleration is expressed as being small. In addition, in the presentspecification, in the case where the body height changes in the state inwhich it is detected or judged that there is a possibility that anobject may be present in a direction of movement of the body, the changeof the body height can be expressed as being abnormal. Since, in thiscase, the body height changes in a manner different from a manner inwhich the body height changes in the case where no object is present,the change of the body height in the former case can be expressed asbeing not normal, i.e., abnormal.

For example, when an actual physical amount is significantly smallerthan a nominal physical amount defined by the manner of operation of theheight controlling actuator, it can be judged that there is apossibility that an object may be present in a direction of movement ofthe body. More specifically described, when, in the above-described casewhere the height controlling actuator is operated to change the bodyheight at a substantially constant speed, the change speed of the bodyheight is decreased to a speed lower than a predetermined speed (thisspeed is defined by the manner of operation of the height controllingactuator), the change acceleration of the body height is decreased to anegative acceleration, or when a differentiated value of the changeacceleration of the body height is decreased to a negative value, it canbe detected or judged that there is a possibility that an object may bepresent.

In addition, as will be described later, the possibility of presence ofobject may be detected based on not the change of the body heightcorresponding to the single wheel but respective changes of a pluralityof body heights corresponding to a plurality of wheels of the vehicle.

(11) The height controlling apparatus according to the mode (9) or (10),wherein said at least one height controlling actuator includes at leastone fluid-flow controlling actuator which controls a working fluid toflow into, and out of, at least one fluid chamber which is providedbetween the body (8) and at least one wheel holding device which holdssaid at least one wheel (4), wherein the actuator control deviceincludes a fluid-flow control portion which controls said at least onefluid-flow controlling actuator so as to change said at least one actualheight, and wherein the height-change-dependent possibility detectingportion includes a change-speed-dependent possibility detecting portionwhich detects that there is said possibility, when a speed of change ofsaid at least one actual height is lower than a reference change speeddetermined based on at least one of a temperature of the working fluidand a pressure of the working fluid in said at least one fluid chamber.

(12) The height controlling apparatus according to the mode (11),wherein the change-speed-dependent possibility detecting portionincludes an abnormal-speed-dependent possibility detecting portion whichdetects that there is said possibility, when the change speed of said atleast one actual height is lower than the reference change speed by morethan a predetermined amount.

In the mode (11), the at least one fluid-flow controlling actuatorcontrols the working fluid to flow into, and out of, the at least onefluid chamber, and thereby controls an amount of the working fluid inthe fluid chamber. Thus, the body height as the relative positionbetween the body and the wheel is controlled. To this end, the workingfluid is caused to flow from a high-pressure source as a sort offluid-pressure source to the fluid chamber, or flow from the fluidchamber to a low-pressure source as another sort of fluid-pressuresource. An amount of the working fluid flowing between the fluid chamberand the fluid-pressure source is greater when a difference of thepressure of the working fluid in the fluid chamber and the pressure ofthe fluid of the fluid-pressure source is great, than when thedifference is small. Since generally the change of the fluid pressure inthe fluid-pressure source is smaller than that in the fluid chamber, itcan be speculated that the above-indicated pressure difference dependsmainly on the fluid pressure in the fluid chamber. For example, when thebody height is increased, the pressure difference between the fluidchamber and the high-pressure source is greater when the fluid pressurein the fluid chamber is low than when it is high, so that a greateramount of the working fluid can flow between the fluid chamber and thehigh-pressure source On the other hand, when the body height isdecreased, the pressure difference between the fluid chamber and thelow-pressure source is greater when the fluid pressure in the fluidchamber is high than when it is low, so that a greater amount of theworking fluid can flow between the fluid chamber and the low-pressuresource.

In addition, a speed of flow of the working fluid flowing between thefluid chamber and the fluid-pressure source is higher when a temperatureof the fluid is high than when it is low.

Thus, the amount of the working fluid flowing between the fluid chamberand the fluid-pressure source is defined by at least one of the fluidpressure in the fluid chamber and the temperature of the working fluid.The change speed of the body height is higher when the flow amount isgreat than when it is small.

Therefore, when an actual change speed of the body height is smallerthan a change speed (i.e., a reference or standard change speed) of thebody height, defined by at least one of the fluid pressure in the fluidchamber and the temperature of the working fluid, it can be judged thatthere is a possibility that an object may be present. Moreover, when anamount obtained by subtracting the actual change speed from thereference change speed is greater than a predetermined amount, i.e., anabnormality judging amount, it can be judged that there is a possibilitythat an object may be present.

As will be described later, it is possible to obtain, for each of aplurality of wheels of the vehicle, an amount calculated by subtractingthe actual change speed from the reference change speed, and judge thegreatest one of the thus obtained amounts as being abnormal, or judgeone or more significantly great amounts of the thus obtained amounts asbeing abnormal.

(13) The height controlling apparatus according to any of the modes (1)through (12), comprising a plurality of said height controllingactuators each of which corresponds to at least one of a plurality ofsaid wheels of the vehicle and change at least one of a plurality ofsaid actual heights respectively corresponding to the plurality ofwheels, wherein the actuator control device includes a same-manneractuator control portion which controls, in a same manner, at least twoheight controlling actuators of the plurality of height controllingactuators so as to respectively change at least two actual heights ofthe plurality of actual heights.

Each of the plurality of height controlling actuators may correspond toa single wheel, or two or more wheels, of the vehicle. In the lattercase, when the each height controlling actuator is operated, two or morebody heights corresponding to the two or more wheels are controlled in asame manner. The above phrase “controls, in a same manner, at least twoheight controlling actuators” means, e.g., that two or more body heightscorresponding to two or more wheels are controlled or changed to a sameheight, that the two or more body heights are changed at a same speed,or that the two or more body heights are changed at a same acceleration.

(14) The height controlling apparatus according to the mode (13),wherein the possibility detecting device includes a firstrelative-change-dependent possibility detecting portion which detectswhether there is said possibility, based on respective changes of saidat least two actual heights changed by said at least two heightcontrolling actuators.

(15) The height controlling apparatus according to the mode (13),wherein the possibility detecting device includes a secondrelative-change-dependent possibility detecting portion which detectswhether there is said possibility, based on respective changes of atleast two physical amounts related to respective speeds of change ofsaid at least two actual heights changed by said at least two heightcontrolling actuators.

In the above-described case where the at least two height controllingactuators are controlled in the same manner, respective changes of atleast two actual heights changed by the at least two height controllingactuators should be equal to each other. Therefore, if the respectivechanges of the at least two actual heights differ from each other, itcan be judged that one of the respective changes of the at least twoactual heights is abnormal. Thus, the possibility of presence of objectcan be judged based on respective changes of at least two physicalamounts related to respective speeds of change of the at least twoactual heights, more generally, a relative change of the at least twoactual heights.

For example, when one of respective change speeds of two actual heightscorresponding to two wheels is smaller than that of the other actualheight by more than a predetermined amount, it can be judged that thereis a possibility that an object may be present in a direction ofmovement of a portion of the vehicle's body that is opposed to one ofthe two wheels that corresponds to the one change speed.

In addition, in the case where the smallest one, V_(min), of respectivechange speeds of four actual heights corresponding to four wheels of thevehicle is significantly smaller than the second smallest one, V_(midL),of those change speeds V_(min)<<V_(midL)), it can be judged that thesmallest change speed V_(min) is abnormal.

Moreover, in the case where the second smallest change speed V_(midL) ofthe respective change speeds of the four actual heights is significantlysmaller than the second greatest one, V_(midH), of those change speeds(V_(midL)<<V_(midH)), it can be judged that there is a possibility thatan object may be present in a direction of movement of each ofrespective portions of the vehicle's body that are opposed to the twowheels corresponding to the smallest change speed V_(min) and the secondsmallest change speed V_(midL). In this case, there is no need tocompare the smallest change speed V_(min) with any other change speedsbecause, if the second smallest change speed V_(midL) is judged as beingabnormal, then it is natural that the smallest change speed V_(min)should be abnormal.

The respective changes of the at least two actual heights can beevaluated based on not the respective change speeds of the at least twoactual heights but respective n-time differentiated values of the changespeeds thereof.

For example, in the case where the smallest one, G_(min), of respectivechange accelerations of the four actual heights is significantly smallerthan the second smallest one, G_(midL), of those change accelerations(G_(min)<<G_(midL)), it can be judged that the smallest changeacceleration G_(min) is abnormal, that is, there is a possibility thatan object may be present in a direction of movement of a portion of thevehicle's body that is opposed to the wheel corresponding to thesmallest change acceleration G_(min); and in the case where the secondsmallest change acceleration G_(midL) is significantly smaller than thesecond greatest one, G_(midH), of the four change acceleration(G_(midL)<<G_(midH)), it can be judged that there is a possibility thatan object may be present in a direction of movement of each ofrespective portions of the vehicle's body that are opposed to the twowheels corresponding to the smallest change acceleration G_(min) and thesecond smallest change acceleration G_(midL).

In addition, in the case where the smallest one, dG_(min), of respectivedifferentiated values of the respective change accelerations of the fouractual heights is significantly smaller than the second smallest one,dG_(midL), of those differentiated values (dG_(min)<<dG_(midL)), it canbe judged that the smallest differentiated value dG_(min) is abnormal;and in the case where the second smallest differentiated value dG_(midL)is significantly smaller than the second greatest differentiated valuedG_(midH) of those differentiated values (dG_(midL)<<dG_(midH)), it canbe judged that the smallest differentiated value dG_(min) and the secondsmallest differentiated value dG_(midL) are abnormal.

(16) The height controlling apparatus according to the mode (14),wherein the first relative-change-dependent possibility detectingportion includes a lowest-change-speed-dependent possibility detectingportion which detects whether there is said possibility, based on alowest change speed of said respective change speeds of said at leasttwo actual heights changed by said at least two height controllingactuators.

When a portion of the vehicle's body bumps on an object, a change speedof a body height corresponding to that portion is decreased. Therefore,in the case where two or more height controlling actuators are operatedto change two or more body heights at a constant speed, it can be judgedthat there is a possibility that an object may be present in a directionof movement of a portion of the vehicle's body that is opposed to thewheel corresponding to the smallest one V_(min) of the respective changespeeds of the two or more body heights.

Alternatively, when the smallest change speed V_(min) is equal to, orsmaller than, an abnormality judging threshold value, V_(th), that isdefined by the manner of operation of the corresponding heightcontrolling actuator (i.e., V_(min)≦V_(th)), it can be judged that thechange of the body height corresponding to the smallest change speedV_(min) is abnormal.

Otherwise, the possibility of presence of object may be detected basedon the smallest one of the respective change speeds of two or more bodyheights and one of the other change speeds. For example, when anabsolute value of a difference of the smallest change speed and thesecond smallest change speed (|V_(midL)−V_(min)|) is equal to, orgreater than, an abnormality judging threshold value, ΔV_(th) (i.e.,|V_(midL)−V_(min)|≧ΔV_(th)), or when the greatest change speed, V_(max),is equal to, or greater than, a normality judging threshold value,V_(thn) (i.e., V_(max)≧ΔV_(thn)), and simultaneously the smallest changespeed V_(min) is equal to, or smaller than, an abnormality judgingthreshold value, V_(th) (i.e., V_(min)≦V_(th)), it can be judged thatthe change of the body height corresponding to the smallest change speedV_(min) is abnormal.

(17) The height controlling apparatus according to the mode (14) or themode (16), wherein the first relative-change-dependent possibilitydetecting portion includes a next-speed-dependent possibility detectingportion which detects that there is said possibility, when an absolutevalue of a difference of two next change speeds out of said respectivechange speeds of said at least two actual heights changed by said atleast two height controlling actuators is greater than a secondreference value, said two next change speeds being next to each other inan order of magnitude of said respective change speeds of said at leasttwo actual heights.

When the absolute value of the difference of the two next change speedsis greater than the reference value, the smaller one of the two nextchange speeds is significantly smaller than the greater change speed,and accordingly it can be judged that the smaller change speed and oneor more change speeds smaller than the smaller change speed areabnormal.

(18) The height controlling apparatus according to any of the modes (14,(16), and (17), wherein the first relative-change-dependent possibilitydetecting portion detects that there is said possibility, when at leasta highest change speed of said respective change speeds of said at leasttwo actual heights changed by said at least two height controllingactuators is higher than a first predetermined speed and an other changespeed of said respective change speeds of said at least two actualheights is lower than a second predetermined speed lower than the firstpredetermined speed.

When at least the highest change speed V_(max) is higher than the firstpredetermined speed, i.e., a normality judging threshold V_(thn), it canbe judged that a current height controlling operation is being normallyperformed. However, when a change speed, V_(ij), of another body heightis lower than the second predetermined speed, i.e., an abnormalityjudging threshold V_(th) (i.e., V_(max)≧V_(thn) and V_(th)≧V_(ij)), itcan be judged that a current height controlling operation is abnormal.

(19) The height controlling apparatus according to the mode (15),wherein the second relative-change-dependent possibility detectingportion includes a lowest-change-acceleration-dependent possibilitydetecting portion which detects whether there is said possibility, basedon a lowest change acceleration of respective accelerations of change ofsaid at least two actual heights changed by said at least two heightcontrolling actuators.

(20) The height controlling apparatus according to the mode (15) or themode (19), wherein the second relative-change-dependent possibilitydetecting portion includes a next-acceleration-dependent possibilitydetecting portion which detects that there is said possibility, when anabsolute value of a difference of two next change accelerations out ofrespective accelerations of change of said at least two actual heightschanged by said at least two height controlling actuators is greaterthan a third reference value, said two next change accelerations beingnext to each other in an order of magnitude of said respective changeaccelerations of said at least two actual heights.

(21) The height controlling apparatus according to any of the modes(15), (19), and (20), wherein the second relative-change-dependentpossibility detecting portion detects that there is said possibility,when at least a highest change acceleration of respective accelerationsof change of said at least two actual heights changed by said at leasttwo height controlling actuators is higher than a first predeterminedacceleration and an other change acceleration of said respective changeaccelerations of said at least two actual heights is lower than a secondpredetermined acceleration lower than the first predeterminedacceleration.

When a portion of the vehicle's body bumps on an object, a changeacceleration of a body height corresponding to that portion is decreasedto a value smaller than zero. Therefore, based on the respective changeaccelerations of two or more body heights, it can be judged that thereis a possibility that an object may be present. In addition, thepossibility of presence of object can be detected at an earlier timingthan a timing when the possibility is detected based on the respectivechange speeds of the two or more body heights.

However, the possibility of presence of object can be detected at astill earlier timing based on respective n-time differentiated values ofthe respective change accelerations of the two or more body heights.

(22) The height controlling apparatus according to any of the modes (15)and (19) through (21), wherein the second relative-change-dependentpossibility detecting portion includes asmallest-differentiated-value-dependent possibility detecting portionwhich detects whether there is said possibility, based on a smallestdifferentiated value of respective differentiated values of respectiveaccelerations of change of said at least two actual heights changed bysaid at least two height controlling actuators.

In each of the above-described modes (13) through (21), change speeds Vmay be replaced with respective differentiated values of changeaccelerations G. For example, when the smallest differentiated valuedG_(min) is equal to, or smaller than, an abnormality judging thresholdvalue dG_(th) (i.e., dG_(min)≦dG_(th)), or when an absolute value of adifference of the smallest differentiated value and the second smallestdifferentiated value dG_(midL) is equal to, or greater than, anabnormality judging threshold value ΔdG_(th) (i.e.,|dG_(midL)−dG_(min)|≧ΔdG_(th)), it can be judged that the change of thebody height corresponding to the smallest differentiated value dG_(min)is abnormal.

Alternatively, when the greatest differentiated value dG_(max) is equalto, or greater than, a normality judging threshold value dG_(thn) equalto, e.g., zero, and simultaneously the smallest differentiated valuedG_(min) is equal to, or smaller than, an abnormality judging thresholdvalue dG_(th) smaller than zero, it can be judged that the change of thebody height corresponding to the smallest differentiated value dG_(min)is abnormal (i.e., dG_(max)≧0 and dG_(min)≦dG_(th)).

(23) The height controlling apparatus according to any of the modes (9)through (22), comprising a plurality of said height controllingactuators including a plurality of fluid-flow controlling actuators,respectively, each of which controls a working fluid to flow into, andout of, at least one of a plurality of fluid chambers which are providedbetween the body and a plurality of wheel holding devices which hold aplurality of said wheels of the vehicle, respectively, wherein theactuator control device includes a fluid-flow control portion whichcontrols the fluid-flow control actuators so as to change a plurality ofsaid actual heights, respectively, which correspond to the wheels,respectively, and wherein the height-change-dependent possibilitydetecting portion includes a change-speed-dependent possibilitydetecting portion which detects whether there is said possibility, basedon at least two absolute values of respective absolute values ofrespective differences between respective speeds of change of the actualheights and respective reference change speeds each of which isdetermined based on at least one of a temperature of the working fluidand a pressure of the working fluid in a corresponding one of the fluidchambers.

For example, the change-speed-dependent possibility detecting portionmay obtain, for each of four wheels of the vehicle, a value, ΔV,calculated by subtracting the change speed of the actual body heightfrom the reference change speed and, if a value (ΔV_(max)−ΔV_(midH))calculated by subtracting, from the greatest one, ΔV_(max), of the thusobtained four values ΔV, the second greatest value, ΔV_(midH), is equalto, or greater than, an abnormality judging threshold value, ΔV_(th)(i.e., ΔV_(max)−ΔV_(midH)≧ΔV_(th)), it can be judged that there is apossibility that an object may be present in a direction of movement ofa portion of the vehicle's body that is opposed to the wheelcorresponding to the greatest value ΔV_(max).

Alternatively, when a difference of the second greatest value ΔV_(midH)and the second smallest value, ΔV_(midL), is equal to, or greater than,an abnormality judging threshold value ΔV_(th) (i.e.,ΔV_(midH)−ΔV_(midL)≧ΔV_(th)), it can be judged that the greatest changespeed ΔV_(max) and the second greatest change speed ΔV_(midH) areabnormal.

In each of the above-described modes (14) through (18), change speeds Vmay be replaced with respective values obtained by subtractingrespective actual change speeds from respective reference change speeds,so that the mode (23) can be applied to the each mode (14) through (18).

(24) The height controlling apparatus according to any of the modes (9)through (23), wherein the height-change-dependent possibility detectingportion includes a posture-change-dependent possibility detectingportion which detects whether there is said possibility, based on atleast one of (a) a change of a posture of the body and (b) a physicalamount related to a speed of change of the posture.

In the present height controlling apparatus, the possibility of presenceof object is detected based on, e.g. an amount of change of the postureof the vehicle's body. From the manner of operation of the at least oneheight controlling actuator, a posture of the body during a heightcontrolling operation (i.e., after a height controlling operation isstarted) can determined. In this case, if a change of a posture of thebody during a height controlling operation, from a posture of the bodybefore the operation, differs from a posture change defined by themanner of operation of the height controlling actuator, it can be judgedthat there is a possibility that an object may be present in a directionof movement of the vehicle's body.

For example, in the case where a plurality of height controllingactuators are operated to change a plurality of body heights,respectively, while keeping a substantially horizontal posture of thevehicle's body, the possibility of presence of object can be detectedwhen the substantially horizontal posture of the vehicle's body when aheight controlling operation is started is changed to an inclinedposture, when an angle of inclination of the body exceeds a referenceangle, or when a speed of increase of the inclination angle exceeds areference speed. The posture of the vehicle's body can be expressed by athree-dimensional vector.

(25) The height controlling apparatus according to the mode (24),wherein the posture-change-dependent possibility detecting portiondetects whether there is said possibility, under a condition that a roadsurface on which the vehicle is stopped is substantially horizontal.

(26) The height controlling apparatus according to the mode (24) or themode (25), comprising a plurality of said height controlling actuatorseach of which corresponds to at least one of a plurality of said wheelsof the vehicle and changes at least one of a plurality of said actualheights respectively corresponding to the plurality of wheels, whereinthe actuator control device includes a posture maintaining portion whichcontrols the plurality of height controlling actuators to change theplurality of actual heights, respectively, while maintaining a postureof the body before the actual heights are changed.

It is desirable that a change of the posture of the vehicle's body bedetected under the condition that the road surface on which the vehicleis stopped is substantially horizontal. In addition, it is desirablethat the plurality of height controlling actuators be operated tomaintain the posture of the body.

Meanwhile, there is known a motor coach (i.e., a big bus) wherein aheight of a front or rear portion of a body that corresponds to a doorthrough which persons can get in, and out of, the coach can be decreased(that is, the coach can take a forward tiling posture or a rearwardtilting posture). In this case, if the posture of the coach does notchange even if one or more height controlling actuators may be operated,it can be judged that there is a possibility that an object may bepresent.

(27) The height controlling apparatus according to any of the modes (9)through (26), wherein the height-change-dependent possibility detectingportion includes a condition-dependent possibility detecting portionwhich detects that there is said possibility, when a predeterminedcondition with respect to the change of said at least one actual heighthas continued for a predetermined time duration.

In the case where the possibility of presence of object is detectedbased on the change of the at least one actual body height, it ispreferred to make a judgment based on a plurality of detected valuesobtained in the predetermined time duration, to a single detected valueobtained at a single timing.

(28) The height controlling apparatus according to any of the modes (1)through (27), wherein the possibility detecting device includes astopped-state-dependent possibility detecting portion which detectswhether there is said possibility, under a condition that a runningspeed of the vehicle is lower than a predetermined speed.

The predetermined speed may be a speed that can be regarded as beingzero (i.e., zero, or a speed that is higher than zero and is defined by,e.g., a detection accuracy of a speed sensor), or an extremely lowspeed. A degree of possibility (i.e., a probability) that an object maybe present is higher when the vehicle is in a stopped state than when itis in a running state. In addition, in the case where the possibility ofpresence of object is detected based on the change of the at least oneactual body height, it is not needed, when the vehicle is in the stoppedstate, to take account of a change of the body height that is caused bythe influence of running of the vehicle. This is advantageous toaccurately detect the possibility. Moreover, there is known such aclearance sonar that is operated under a condition that the runningspeed of a vehicle is lower than a predetermined speed.

(29) The height controlling apparatus according to any of the modes (1)1 through (28), wherein the possibility detecting device includes anenvironment-change-dependent possibility detecting portion which detectswhether there is said possibility, based on a change of an environmentaround the vehicle.

(30) The height controlling apparatus according to the mode (29),wherein the environment-change-dependent possibility detecting portionincludes a getting-in-and-out detecting portion which detects at leastone of (a) a person who gets in the vehicle and (b) a person who getsout of the vehicle.

Whether a person gets in, or out of, the vehicle can be detected basedon whether a door is opened or closed, or based on the change of the atleast one actual body height.

(31) The height controlling apparatus according to any of the modes (1)through (30), wherein the possibility detecting device includes apossibility-degree detecting portion which detects each of a pluralityof different degrees of said possibility.

The possibility-degree detecting portion can detect each of thedifferent degrees of the possibility, based on, e.g., arelative-positional relationship between the vehicle's body and theobject present around the vehicle, or the change of the at least oneactual height.

For example, a higher degree of possibility is detected when a distancebetween the body and the object present around the vehicle is small thanwhen the distance is great, or when the body and the object approacheach other than when the two elements move away from each other. Inaddition, a higher degree of possibility is detected when a change speedof the actual body height is low than when the change speed is high, orwhen a differentiated value of a change acceleration of the actual bodyheight is small than when the differentiated value is great.

(32) The height controlling apparatus according to any of the modes (1)through (31), wherein the actuator control device includes a high-speedactuator control portion which controls said at least one heightcontrolling actuator to change said at least one actual height at aspeed higher than a predetermined height-change speed; and a low-speedactuator control portion which controls said at least one heightcontrolling actuator to change said at least one actual height at aspeed not higher than the predetermined height-change speed, and whereinthe possibility detecting device includes a high-speed-control-relatedpossibility detecting portion which detects whether there is saidpossibility, in a case where the high-speed actuator control portioncontrols said at least one height controlling actuator.

It is more highly needed to detect the possibility of presence ofobject, when the actual body height is changed at a high speed than whenit is changed at a low speed.

The high-speed-control-related possibility detecting portion detectswhether there is the possibility, before or after the high-speedactuator control portion starts controlling the height controllingactuator. In the case where the possibility detecting portion detectswhether there is the possibility, before the actuator control portionstarts controlling the height controlling actuator, the actuator controlportion may not start controlling the height controlling actuator.

(33) The height controlling apparatus according to any of the modes (1)through (32), wherein the movement restraining portion includes at leastone of (a) a movement-stopping control portion which controls, when thepossibility detecting device detects that there is said possibility,said at least one height controlling actuator to stop the movement ofthe body, and (b) a direction-reversing control portion which reverses,when the possibility detecting device detects that there is saidpossibility, said direction of the movement of the body so that the bodyis moved in a reversed direction.

When the possibility of presence of object is detected, the heightcontrolling actuator is controlled to stop the movement of the vehicle'sbody, or reverse the direction of the movement of the body so that thebody is moved in the reversed direction. In the former case, theoperation of the height controlling actuator may be stopped, or theheight controlling actuator may be operated to move the body in areverse direction. If the body is moved in the reverse direction, themovement of the body can be quickly stopped against the inertia of thebody.

(34) The height controlling apparatus according to the mode (33),wherein the movement restraining portion includes (b) the directionreversing portion, and wherein the direction reversing portion includesa maximum-speed control portion which reverses said direction of themovement of the body so that the body is moved at a maximum speed in thereversed direction.

When the possibility of presence of object is detected, it is preferredto reverse the direction of the movement of the body and quickly movethe body in the reversed direction. In the case where the heightcontrolling actuator includes an electric motor, the maximum-speedcontrol portion controls an electric current supplied to the electricmotor so that the electric motor produces a maximum output; and in thecase where the height controlling actuator includes a fluid-flowcontrolling actuator, the maximum-speed control portion controls a fluidflow so that a maximum amount of the working fluid flows into, or outof, a fluid chamber. More specifically described, in the case where thepresent height controlling apparatus includes a fluid chamber providedbetween the body and the wheel; a fluid-pressure source; and a controlvalve provided between the fluid-pressure source and the fluid chamber,the actual body height can be increased by opening the control valve bya maximum amount (when the control valve is operated under a duty-cyclecontrol, the duty cycle or ratio (=(duty time)/(duty time+off-duty time)is selected at 1) and causing a maximum amount of working fluid to flowfrom the fluid-pressure source to the fluid chamber.

(35) The height controlling apparatus according to any of the modes (1)through (34), wherein the movement restraining portion includes aspeed-decrease control portion which controls, when the possibilitydetecting device detects that there is said possibility, said at leastone height controlling actuator to decrease a speed of the movement ofthe body in said direction.

It is reasonable that when the possibility of presence of object isdetected, the speed of the movement of the vehicle's body is decreased.

(36) The height controlling apparatus according to any of the modes (1)through (35), wherein the possibility detecting device includes apossibility-degree detecting portion which detects each of a pluralityof different degrees of said possibility, and wherein the movementrestraining portion includes a possibility-degree-dependent actuatorcontrol portion which controls said at least one height controllingactuator in each of a plurality of different manners corresponding tothe plurality of different degrees of said possibility, respectively.

Since the possibility-degree-dependent actuator control portion controlsthe height controlling actuator according to the detected degree of thepossibility, a frequency at which the height controlling actuator isuselessly operated can be reduced as compared with the case where theheight controlling actuator is operated independent of degrees of thepossibility.

(37) The height controlling apparatus according to the mode (36),wherein the possibility-degree-dependent actuator control portioncontrols, when the degree of said possibility detected by thepossibility-degree detecting portion is higher than a predetermineddegree, the at least one height controlling actuator to reverse saiddirection of the movement of the body so that the body is moved in areversed direction, and controls, when the detected degree of saidpossibility is not higher than the predetermined degree, said at leastone height controlling actuator to stop the movement of the body in saiddirection.

(38) The height controlling apparatus according to the mode (36),wherein the possibility-degree-dependent actuator control portioncontrols, when the degree of said possibility detected by thepossibility-degree detecting portion is higher than a predetermineddegree, said at least one height controlling actuator to reverse saiddirection of the movement of the body so that the body is moved in areversed direction, and controls, when the detected degree of saidpossibility is not higher than the predetermined degree, said at leastone height controlling actuator to decrease a speed of the movement ofthe body in said direction.

In the case where three or more degrees of the possibility are detected,the direction of the movement of the body may be reversed according tothe highest degree; the movement of the body may be stopped according tothe medium degree; and the speed of the movement of the body may bedecreased according to the lowest degree.

Alternatively, the possibility-degree-dependent actuator control portionmay control, when the degree of the possibility is higher than apredetermined degree, the height controlling actuator to stop themovement of the body and controls, when the degree of the possibility isnot higher than the predetermined degree, the height controllingactuator to decrease the speed of the movement of the body in thedirection.

(39) The height controlling apparatus according to any of the modes (36)through (38), wherein the possibility-degree-dependent actuator controlportion includes a speed control portion which controls said at leastone height controlling actuator to control a speed of the movement ofthe body such that the higher the degree of said possibility detected bythe possibility-degree detecting portion is, the lower the speed of themovement of the body is.

It is less needed to decrease the speed of the movement of the body,when the degree of the possibility is low than when the degree of thepossibility is high. Therefore, it is desirable that the heightcontrolling actuator be operated to control the speed of the movement ofthe body such that the higher the degree is, the lower the speed is.Alternatively, the height controlling actuator may be operated such thatwhen the degree of the possibility is higher than a first predetermineddegree, the movement of the body is stopped; and when the degree of thepossibility is lower than a second predetermined degree lower than thefirst degree, the movement of the body is not stopped, i.e., iscontinued (i.e., an amount of decreasing of the speed is zero). Thestopping of the movement of the body means that an amount of decreasingof the speed is maximum.

(40) The height controlling apparatus according to any of the modes (1)through (39), wherein the actuator control portion includes an operationresuming portion which resumes, when at least one predetermined resumingcondition including a condition that the movement of the body in saiddirection has been stopped by said at least one height controllingactuator under control of the movement restraining portion and at leastone door of the vehicle has been changed from an opened state thereof toa closed state thereof, is met, an operation of said at least one heightcontrolling actuator so as to change said at least one actual height.

(41) The height controlling apparatus according to the mode (40),wherein the operation resuming portion judges, when a time duration inwhich said at least one door of the vehicle has been kept in the openedstate thereof is shorter than a predetermined time duration, that saidat least one predetermined resuming condition has been met, and resumesthe operation of said at least one height controlling actuator.

When one of the doors of the vehicle has been changed from its openedstate to its closed state, it can be judged that there is a high degreeof possibility that a person may have got out of the vehicle and anobject such as luggage may be present around the vehicle. In this case,however, if the time duration in which the door has been kept to itsopened state is short, it can be judged that there is a low degree ofpossibility that a person may have got out of the vehicle and an objectmay be present around the vehicle.

Hence, it is reasonable that when the at least one predeterminedresuming condition including the condition that the door has beenchanged from the opened state to the closed state is met, the operationof the height controlling actuator is resumed.

However, the present mode (41) may be applied to only the case where thepossibility detecting device detects the possibility of presence ofobject, because the door has been changed from the opened state to theclosed state, and accordingly the movement restraining portion stopschanging the actual body height. In addition, a higher degree of thepossibility that an object may be present around the vehicle may bedetected when the time duration in which the door has been kept to itsopened state is long than when it is short.

(42) The height controlling apparatus according to the mode (40) or themode (41), wherein the operation resuming portion resumes the operationof said at least one height controlling actuator in a different mannerthan a manner in which the actuator control portion has controlled saidat least one height controlling actuator before the operation thereof isresumed.

For example, it is desirable that when the operation of the heightcontrolling actuator is resumed, the speed of the movement of thevehicle's body be decreased. In addition, after the resumption of theoperation, the body can be moved at a lower speed when the time durationin which the door has been kept to its opened state is long than when itis short.

(43) The height controlling apparatus according to any of the modes (1)through (42), wherein the actuator control device includes a high-speedactuator control portion which controls said at least one heightcontrolling actuator to change said at least one actual height at aspeed higher than a predetermined height-change speed; a low-speedactuator control portion which controls said at least one heightcontrolling actuator to change said at least one actual height at aspeed not higher than the predetermined height-change speed; and ahigh-speed-control-related actuator control portion which controls, whenthe high-speed actuator control portion controls said at least oneheight controlling actuator and the possibility detecting device detectsthat there is said possibility, said at least one height controllingactuator to restrain the movement of the body in said direction andwhich does not control, when the low-speed actuator control portioncontrols said at least one height controlling actuator and thepossibility detecting device detects that there is said possibility,said at least one height controlling actuator to restrain the movementof the body in said direction.

If the possibility that an object may be present in a direction ofmovement of the vehicle's body is detected when the high-speed actuatorcontrol portion controls the height controlling actuator, the movementof the body in that direction is restrained; but even if the possibilityof presence of object may be detected when the low-speed actuatorcontrol portion controls the height controlling actuator, the movementof the body in that direction is not restrained.

(44) The height controlling apparatus according to the mode (43),wherein the high-speed actuator control portion includes ahigh-speed-control-request-dependent actuator control portion whichcontrols, in response to a predetermined high-speed height-changerequest, said at least one height controlling actuator to change said atleast one actual height at the speed higher than the predeterminedheight-change speed.

When the predetermined high-speed height-change request or need isdetected or recognized, the height controlling actuator is operated tochange the actual body height at the high speed. For example, ahigh-speed height-change request or need to quickly change the bodyheight to a target height is detected or recognized (a) when the bodyheight is changed to a height suitable for a person to get in thevehicle, (b) when the body height is changed, after a person has got inthe vehicle, to a height suitable for the vehicle to run, or (c) whenthe body height is changed to a height suitable for a person to get outof the vehicle.

(45) The height controlling apparatus according to any of the modes (1)through (44), comprising a plurality of said height controllingactuators each of which corresponds to at least one of a plurality ofsaid wheels of the vehicle and changes at least one of a plurality ofsaid actual heights each of which is defined as a relative position of acorresponding one of a plurality of portions of the body thatrespectively correspond to the plurality of wheels, and a correspondingone of the wheels, wherein the possibility detecting device includes aplurality of individual height-change detecting portions which detectrespective changes of the actual heights; and a plurality of individualheight-change-dependent possibility detecting portions each of whichdetects, based on the change of a corresponding one of the actualheights that is detected by a corresponding one of the individualheight-change detecting portions, whether there is the possibility thatthe object may be present in the direction in a corresponding one of theportions of the body is moved to change said corresponding actualheight, and wherein the movement restraining portion includes at leastone of (a) a partly stopping portion which does not control, when atleast one individual height-change-dependent possibility detectingportion as a part of the individual height-change-dependent possibilitydetecting portions detects that there is the possibility that the objectmay be present in the direction in which a corresponding one of theportions of the body is moved, at least a corresponding one of theheight controlling actuators so as not to change a corresponding one ofthe actual heights, and (b) a fully stopping portion which does notcontrol, when at least one individual height-change-dependentpossibility detecting portion as a part of the individualheight-change-dependent possibility detecting portions detects thatthere is the possibility that the object may be present in the directionin which a corresponding one of the portions of the body is moved, eachof the height controlling actuators so as not to change any of theactual heights.

If the at least one individual height-change-dependent possibilitydetecting portion as a part of the individual height-change-dependentpossibility detecting portions detects that there is the possibilitythat an object may be present in the direction in which front left andright portions (or rear left and right portions) of the vehicle's bodyare moved, the height controlling actuators corresponding to the frontleft and right wheels (or the rear left and right wheels) are notoperated to change the corresponding actual body heights. In this case,if the height controlling actuators corresponding to the two remainingwheels are operated to change the corresponding actual body heights, aheight of a lengthwise end portion of the body that is located in front(or rear) of the two front wheels (or the two rear wheels) is changed ina direction opposite to the direction in which the two actual bodyheights are changed by the two height controlling actuatorscorresponding to the two remaining wheels. Thus, in this case, it is notneeded to control the two height controlling actuators corresponding tothe above-indicated front left and right wheels (or the above-indicatedrear left and right wheels) so as to reverse the direction in which thecorresponding body heights are changed. Alternatively, if thepossibility of presence of object is detected in a direction of movementof a portion of the body that corresponds to only one of the two front(or rear) wheels, the two height controlling actuators corresponding toboth the two front (or rear) wheels may not be operated.

On the other hand, if the possibility of presence of object is detectedin a direction of movement of each of two portions of the body that arelocated on a diagonal line of the body, all the four height controllingactuators corresponding to the four wheels may not be operated. In thiscase, the balance of the four body heights can be prevented from beingbroken.

(46) The height controlling apparatus according to any of the modes (1)through (45), wherein the actuator control portion includes an informingdevice which informs, when the actuator control portion controls said atleast one height controlling actuator and the possibility detectingportion detects that there may be said possibility, at least one of (a)that said at least one actual height is controlled and (b) that there issaid possibility.

The informing device informs a person (e.g., a driver) of at least oneof (a) that the at least one actual height is controlled and (b) thatthere is the possibility of presence of object. In addition, theinforming device may include at least one of a device that outputs theinformation in a visible manner and a device that outputs theinformation in an audible manner. Moreover, the informing device mayinclude at least one of a device that outputs the information toward aperson inside the vehicle and a device that outputs the informationtoward a person outside the vehicle.

The informing device may be a device that is exclusively used forachieving the above-indicated aim, or a device that is mainly used forachieving a different aim. In the latter case, an outside lamp providedoutside the vehicle, such as a head lamp, a fog lamp, a cornering lamp,a turn signal lamp, or a stop lamp; an inside lamp provided on aninstrument panel, such as a hazard lamp; a horn that produces soundstoward a person outside the vehicle; or a speaker of an audio device ora navigation device.

In the case where the informing device can be additionally used toinform a person of a fact that the vehicle has a failure, it isdesirable that when the informing device is used to inform at least oneof (a) that the at least one actual height is controlled and (b) thatthere is the possibility of presence of object, the informing device beoperated in a manner distinguishable from the manner in which it is usedto inform that the vehicle has a failure.

(47) The height controlling apparatus according to the mode (46),wherein the possibility detecting device includes a possibility-degreedetecting portion which detects each of a plurality of different degreesof said possibility, and wherein the informing device operates in eachof a plurality of different manners corresponding to the plurality ofdifferent degrees of said possibility, respectively.

In the present height controlling apparatus, the informing device caninform a person of the detected degree of the possibility of presence ofobject.

For example, in the case where the informing device includes a firstdevice (e.g., a lamp or a display) that outputs the information in avisible manner and a second device (e.g., a horn or a speaker) thatoutputs the information in an audible manner, both the first and seconddevices may be operated to output the information, when the degree ofthe possibility is high; and either one of the first and second devicesmay be operated to output the information, when the degree of thepossibility is low. In addition, in the case where the informing deviceincludes a third device that outputs the information toward a personinside the vehicle and a fourth device that outputs the informationtoward a person outside the vehicle, both the third and fourth devicesmay be operated to output the information, when the degree of thepossibility is high; and either one of the third and fourth devices maybe operated to output the information, when the degree of thepossibility is low.

(48) The height controlling apparatus according to any of the modes (1)through (47), wherein the actuator control portion includes anin-emergency stopping portion which stops the movement of the body insaid direction, in response to an in-emergency stopping command.

In the present height controlling apparatus, the in-emergency stoppingportion can stop the movement of the body, for example, in response torecognition of a person's voice; detection of bumping of the vehicle'sbody against an object; information received from a portable controllerworn by, e.g., a driver; or operation of an in-emergency operablemember. If a person contacts the body, then an electric current flowingthrough the body is grounded. Thus, a fact that a person has contactedthe body can be detected by detecting the electric current flowingthrough the body. In each case, the vehicle's body and/or the object canbe prevented from being damaged, or the damage can be minimized.

Alternatively, the actuator control portion may control the heightcontrolling actuator to reverse the direction of the movement of thevehicle's body, in response to an in-emergency control command.

(49) The height controlling apparatus according to any of the modes (1)through (48), wherein said at least one height controlling actuatorincludes at least one fluid-flow control actuator which controls aworking fluid to flow into, and out of, at least one fluid chamber whichis provided between the body and at least one wheel holding device whichholds said at least one wheel, wherein the apparatus further comprises:

an accumulator which stores the working fluid in a pressurized state andcan supply the pressurized working fluid to said at least one fluidchamber;

a pumping device which supplies, to the accumulator, the working fluidin the pressurized state; and

a pumping-device control portion which controls, after an ignitionswitch is switched from an ON state thereof to an OFF state thereof, thepumping device so that a pressure of the working fluid stored by theaccumulator is kept higher than a predetermined pressure.

In the present height controlling apparatus, after the ignition switchis switched from its ON state to its OFF state, the pumping device isoperated so that the pressure of the working fluid in the accumulator iskept higher than the predetermined pressure. Therefore, even if ahigh-pressure fluid may be needed in the state in which the ignitionswitch is in the OFF state, the accumulator can quickly supply thehigh-pressure fluid to the fluid chamber.

In the state in which the ignition switch is in the ON state, too, thepumping-device control portion controls the pumping device so that thepressure of the working fluid in the accumulator may fall within apredetermined pressure range higher than the predetermined pressurevalue.

(50) A height controlling apparatus for controlling at least one actualheight as a relative position of a body of a vehicle and at least onewheel of the vehicle, the apparatus comprising:

at least one height controlling actuator which changes said at least oneactual height;

a height-control judging device which judges whether it is desirable tocontrol said at least one actual height; and

an actuator control device which controls said at least one heightcontrolling actuator according to a judgment made by the height-controljudging device.

In the present height controlling apparatus, the actuator control devicecontrols, according to the judgment made by the height-control judgingdevice, the height controlling actuator to change the speed of thechanging of the actual body height, stop the changing of the actual bodyheight, or change the direction of the changing of the actual bodyheight, or not to start the changing of the actual body height.

Whether it is desirable to control the actual body height can be judgedbased on a current condition of the vehicle or an environment around thevehicle.

The height controlling apparatus in accordance with the present mode(50) may be combined with the technical feature in accordance with anyof the modes (1) through (49).

(51) A height controlling apparatus for controlling at least one actualheight as a relative position of a body of a vehicle and at least onewheel of the vehicle, the apparatus comprising:

at least one height controlling actuator which changes said at least oneactual height;

an operation detecting device detects whether at least one operation outof an energy-source supplying operation, an oil changing operation, aroof-carrier loading operation, a roof-carrier repairing operation, anda vehicle washing operation is being performed; and

a height-control inhibiting portion which inhibits, when the operationdetecting device detects that said at least one operation is beingperformed, said at least one height controlling actuator from changingsaid at least one actual height.

Since at least one of the energy-source supplying operation, the oilchanging operation, the roof-carrier loading operation, the roof-carrierrepairing operation, and the vehicle washing operation is detected, theheight controlling actuator is inhibited from changing the actual bodyheight. Therefore, the at least one operation can be prevented frombeing adversely influenced by the changing of the body height. If the atleast one operation is detected before the changing of the body heightis started, then the changing of the body height is not started; and ifthe at least one operation is detected after the changing of the bodyheight is started, then the changing of the body height is stopped oraborted.

The height controlling apparatus in accordance with the present mode(51) may be combined with the technical feature in accordance with anyof the modes (1) through (50).

(52) A height controlling apparatus for controlling at least one actualheight as a relative position of at least one portion of a body of avehicle that corresponds to at least one wheel of the vehicle, and saidat least one wheel, the apparatus comprising:

at least one fluid chamber which is provided between said at least oneportion of the body and at least one wheel holding device which holdssaid at least one wheel;

at least one fluid-flow control actuator which controls a working fluidto flow into, and out of, said at least one fluid chamber so as tochange said at least one actual height;

an accumulator which stores the working fluid in a pressurized state andcan supply the pressurized working fluid to said at least one fluidchamber;

a pumping device which supplies, to the accumulator, the working fluidin the pressurized state; and

a pumping-device control portion which controls, after an ignitionswitch is switched from an ON state thereof to an OFF state thereof, thepumping device so that a pressure of the working fluid stored by theaccumulator is kept higher than a predetermined pressure.

The height controlling apparatus in accordance with the present mode(52) may be combined with the technical feature in accordance with anyof the modes (1) through (51).

(53) A height controlling apparatus for controlling at least one actualheight as a relative position of at least one portion of a body of avehicle that corresponds to at least one wheel of the vehicle, and saidat least one wheel, the apparatus comprising:

at least one fluid chamber which is provided between said at least oneportion of the body and at least one wheel holding device which holdssaid at least one wheel;

at least one fluid-flow control actuator which controls a working fluidto flow into, and out of, said at least one fluid chamber so as tochange said at least one actual height;

an accumulator which stores the working fluid in a pressurized state andcan supply the pressurized working fluid to said at least one fluidchamber;

a pumping device which supplies, to the accumulator, the working fluidin the pressurized state; and

a pumping-device control portion which controls, when an ignition switchis in an OFF state thereof, the pumping device so that a pressure of theworking fluid stored by the accumulator falls within a predeterminedpressure range.

The height controlling apparatus in accordance with the present mode(51) may be combined with the technical feature in accordance with anyof the modes (1) through (50).

BRIEF DESCRIPTION OF THE DRAWINGS

The above and optional objects, features, and advantages of the presentinvention will be better understood by reading the following detaileddescription of the preferred embodiments of the invention whenconsidered in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view of a suspension system employing a heightcontrolling apparatus to which the present invention is applied;

FIG. 2A is a plan view of a vehicle including the suspension system;

FIG. 2B is a side elevation view of the vehicle;

FIG. 3 is a diagrammatic view of a suspension ECU (electronic controlunit) of the suspension system;

FIG. 4 is a flow chart representing a height controlling program that isstored by a storing portion of the suspension ECU;

FIG. 5 is a flow chart representing a portion of the height controllingprogram;

FIG. 6 is a flow chart representing another portion of the heightcontrolling program;

FIG. 7 is a flow chart representing another portion of the heightcontrolling program;

FIG. 8 is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 9A is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 9B is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 9C is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 10 is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 11 is a flow chart representing another portion of the heightcontrolling program of FIG. 10;

FIG. 12 is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 13 is a map representing a standard-speed determining table thatmay be stored by the storing portion of the suspension ECU;

FIG. 14 is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU;

FIG. 15 is a map representing another standard-speed determining tablethat may be stored by the storing portion of the suspension ECU;

FIG. 16 is a flow chart representing a pumping-device controllingprogram that may be stored by the storing portion of the suspension ECU;and

FIG. 17 is a flow chart representing a portion of another heightcontrolling program that may be stored by the storing portion of thesuspension ECU.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, there will be described a vehicle's suspension systememploying a height controlling apparatus to which the present inventionis applied. The suspension system is a four-wheel independent suspensionsystem that is employed by a four-wheel-drive vehicle, and is common toall embodiments of the height controlling apparatus that will bedescribed in detail later.

As shown in FIG. 1, the suspension system includes four suspensioncylinders 10 (10FL, 10FR, 10RL, 10RR) and corresponding suspensionsprings, not shown, that are provided between four wheel holding devices6 (6FL, 6FR, 6RL, 6RR) and a vehicle's body 8, respectively. The fourwheel holding devices 6 (6FL, 6FR, 6RL, 6RR) hold four wheels 4 (i.e., afront left wheel 4FL, a front right wheel 4FR, a rear left wheel 4RL,and a rear right wheel 4RR), respectively.

The four suspension cylinders 10 have an identical construction, andeach suspension cylinder 10 includes a housing 11; a piston 12 that fitsin an inner space of the housing 11 such that the piston 12 is movablerelative to the housing 11; and a piston rod 14. The piston rod 14 isconnected to a corresponding one of the four wheel holding devices 6,such that the piston rod 14 is not movable relative to the correspondingwheel holding device 6 in a vertical direction, and the housing 11 isconnected to the vehicle's body 8 such that the housing 11 is notmovable relative to the body 8 in the vertical direction.

The piston 12 divides the inner space of the housing 11 into two liquidchambers 16, 18, and has a communication passage 20 with an invariablerestrictor. When the piston 12 is moved relative to the housing 11 by amovement of a corresponding one of the four wheels 4 relative to thevehicle's body 8, a working liquid as a sort of working fluid movesbetween the two liquid chambers 16, 18 through the communication passage20. Thus, the communication passage 20 with the restrictor produces adamping force, and each suspension cylinder 10 functions as a shockabsorber.

The respective first liquid chambers 16 of the four suspension cylinders10 (10FL, 10FR, 10RL, 10RR) are communicated with four individualpassages 22 (22FL, 22FR, 22RL, 22RR), respectively, that arecommunicated, in parallel, with four high-pressure accumulators 24(24FL, 24FR, 24RL, 24RR), respectively, and with four low-pressureaccumulators 26 (26FL, 26FR, 26RL, 26RR), respectively, that correspondto the four suspension cylinders 10 (10FL, 10FR, 10RL, 10RR),respectively. Four spring-constant switching valves 28 (28FL, 28FR,28RL, 28RR) are provided between the four suspension cylinders 10 (10FL,10FR, 10RL, 10RR) and the four low-pressure accumulators 26 (26FL, 26FR,26RL, 26RR), respectively.

Each of the accumulators 24, 26 functions as a spring. For example, eachaccumulator 24, 26 includes a housing and a partition member thatdivides an inner space of the housing into two volume-changeablechambers one of which is communicated with the corresponding individualpassage 22 and the other of which is filled with an elastic body. As thevolume of one of the two chambers is increased, the volume of the otherchamber is decreased, so that the each accumulator 24, 26 produces anelastic force. Each accumulator 24, 26 may be of a bellows type, of abladder type, or of a piston type.

In the present embodiment, each high-pressure accumulator 24 has aspring constant greater than that of each low-pressure accumulator 26,as described above. Thus, each accumulator 24 is called thehigh-pressure accumulator, and each accumulator 26 is called thelow-pressure accumulator. Each of the spring-constant switching valves28 is a solenoid-operated open/close valve that is normally open.

The four individual passages 22 (22FL, 22FR, 22RL, 22RR) have respectivevariable restrictors 30 (30FL, 30FR, 30RL, 30RR). As described above,when each of the four wheels 4 is moved relative to the body 8 in thevertical direction, the working liquid flows into, or out of, the firstliquid chamber 16 of the corresponding suspension cylinder 10. Each ofthe four variable restrictors 30 controls a flow area (i.e., atransverse cross-section area) of the corresponding individual passage22 and thereby controls the damping force produced by the correspondingsuspension cylinder 10. Thus, in the present embodiment, each variablerestrictor 30 constitutes a damping-force controlling device.

The four suspension cylinders 10FL, 10FR, 10RL, 10RR are connected to acenter cylinder 52 via the respective individual passages 22FL, 22FR,22RL, 22RR.

The center cylinder 52 includes a housing 54 and a control piston 56that fits in an inner space of the housing 54 such that the controlpiston 56 is slideable on an inner circumferential surface of thehousing 54. The control piston 56 includes two end pistons 58, 59 and aconnection member 60 connecting between the two end pistons 58, 59. Theconnection member 60 passes through a partition wall 62 that cooperateswith the two end pistons 58, 59 to divide the inner space of the housing54 into four liquid chambers 64, 65, 66, 67. More specificallydescribed, the four liquid chambers 64, 65, 66, 67 include two innerliquid chambers 64, 65 that are defined by the partition wall 62 and thetwo end pistons 58, 59; and two outer liquid chambers 66, 67 that aredefined by the two end pistons 58, 59 and two opposite end walls of thehousing 54. The first outer liquid chamber 66 is connected to thesuspension cylinder 10FL corresponding to the front left wheel 4FL; thesecond outer liquid chamber 67 is connected to the suspension cylinder10FR corresponding to the front right wheel 4FR; the first inner liquidchamber 64 is connected to the suspension cylinder 10RL corresponding tothe rear left wheel 4RL; and the second inner liquid chamber 65 isconnected to the suspension cylinder 10RR corresponding to the rearright wheel 4RR.

In the following description, when it is needed to discriminate the foursuspension cylinders 10, the four high-pressure accumulators 24, thefour low-pressure accumulators 26, and so on, from each other, symbolsFL, FR, RL, RR representing the corresponding positions in the vehicleare added to the reference numerals 10, 24, 26, . . . ; and when it isnot, those symbols are not added.

The present suspension system employs a height controlling apparatus 74that includes a high-pressure source 76; a reservoir 78 as alow-pressure source; and an individual valve device 89.

The high-pressure source 76 includes a pumping device 84 including apump 81 and a pump motor 82; and a pressure storage accumulator 86. Thepumping device 84 and the pressure storage accumulator 86 arecommunicated with a control passage 88. The pump 81 pumps up the workingliquid from the reservoir 78, and outputs the pressurized workingliquid, so that the pressurized working liquid is stored by the pressurestorage accumulator 86. The accumulator 86 is communicated with thecontrol passage 88 via a pressure storage control valve 90 as asolenoid-operated open/close valve that is normally closed. Anaccumulator pressure sensor 92 that detects a pressure of the workingliquid stored by the accumulator 86, is communicated with theaccumulator 86 directly, i.e., without intervention of the pressurestorage control valve 90.

The control passage 88 has, on a liquid-output side of the pump 81, acheck valve 94 and a noise reduction accumulator 96. A flow-out passage104 connects between a high-pressure side and a low-pressure side of thepump 81, and has a flow-out control valve 106 as a solenoid-operatedopen/close valve that is normally closed.

The individual valve device 89 is associated with four individualcontrol passages 108 (108FL, 108FR, 108RL, 108RR) each of which connectsbetween the common control passage 88 and a corresponding one of thefour individual passages 22 (22FL, 22FR, 22RL, 22RR). The fourindividual control passages 108 (108FL, 108FR, 108RL, 108RR) haverespective individual control valves 110 (110FL, 110FR, 110RL, 110RR).In addition, the two individual control passages 108FL, 108FR areconnected to each other by a front-side communication passage 111 havinga first communication valve 112; and the other, two individual controlpassages 108RL, 108RR are connected to each other by a rear-sidecommunication passage 113 having a second communication valve 114.

Each of the four individual control valves 110FL, 110FR, 110RL, 110RRand the two communication valves 112, 114 is a solenoid-operatedopen/close valve that is normally closed. When each one of the fourindividual control valves 110FL, 110FR, 110RL, 110RR is controlledindependent of the other individual control valves 110 in the state inwhich the two communication valves 112, 114 are closed, a body heightwith respect to a corresponding one of the four wheels 4FL, 4FR, 4RL,4RR can be controlled independent of respective body heights withrespect to the other wheels 4. In the present embodiment, a body heightwith respect to each one of the four wheels 4FL, 4FR, 4RL, 4RR isdefined as a relative position (or a distance) between a correspondingone of the four wheels 4FL, 4FR, 4RL, 4RR (or a corresponding one of thefour wheel holding devices 6FL, 6FR, 6RL, 6RR) and a corresponding oneof four portions of the vehicle's body 8 to which the four suspensioncylinders 10FL, 10FR, 10RL, 10RR are connected, respectively. Inaddition, when each one of the two communication valves 112, 114 isoperated, two body heights with respect to a corresponding pair ofwheels 4 out of the pair of front wheels 4FL, 4FR and the pair of rearwheels 4RL, 4RR are controlled either to a same height or to respectivedifferent heights.

In the present embodiment, respective solenoids of the four individualcontrol valves 110, the pressure storage control valve 90, and theflow-out control valve 106, and a drive circuit that drives the pumpmotor 82 cooperate with each other to constitute four body-heightcontrolling actuators 120. The four body-height controlling actuators120 are operated to control respective amounts of the working liquid inthe respective first liquid chambers 16 of the four suspension cylinders10 and thereby move the four portions of the vehicle's body 8,respectively. The four body-height controlling actuators 120 areassociated with the four wheels 4, respectively, and the respectivesolenoids of the pressure storage control valve 90 and the flow-outcontrol valve 106, and the drive circuit that drives the pump motor 82are common to the four wheels 4. For example, the body-heightcontrolling actuator 120FL associated with the front left wheel 4FL isconstituted by the respective solenoids of the individual control valve110FL, the pressure storage control valve 90, and the flow-out controlvalve 106, and the drive circuit that drives the pump motor 82; and thebody-height controlling actuator 120FR associated with the front rightwheel 4FR is constituted by the respective solenoids of the individualcontrol valve 110FR, the pressure storage control valve 90, and theflow-out control valve 106, and the drive circuit that drives the pumpmotor 82. A suspension ECU (electronic control unit) 200 that controlsthe four body-height controlling actuators 120 constitutes an actuatorcontrol device.

However, it can be said that the four suspension cylinders 10 constitutefour body-height controlling actuators, respectively. In this case, therespective solenoids of the four individual control valves 110, thepressure storage control valve 90, and the flow-out control valve 106,and the drive circuit that drives the pump motor 82 cooperate with eachother to constitute an actuator control device that controls therespective amounts of the working liquid in the respective first liquidchambers 16 of the four suspension cylinders 10 as the four body-heightcontrolling actuators.

The present suspension system is controlled by the suspension ECU 200that is essentially constituted by a computer. As shown in FIG. 3, thesuspension ECU 200 includes an implementing portion 204, a storingportion 206, and an input/output (I/O) portion 208. The respective coils(or solenoids) of the four spring-constant switching valves 28, the fourvariable restrictors 30, the pressure storage control valve 90, the fourindividual control valves 110, the two communication valves 112, 114,the flow-out control valve 106, and the pump motor 81, all shown in FIG.1, are connected to the I/O portion 208 via respective drive circuits,not shown. In addition, an informing device 210, shown in FIG. 3, andthe accumulator-pressure sensor 92 are connected to the I/O portion 208.Other elements that are connected to the I/O portion 208 are as follows:four suspension-cylinder-pressure sensors 218 that detect respectivepressures of the working liquid in the respective first liquid chambers16 of the four suspension cylinders 10; four body-height sensors 220that are associated with the four wheels 4, respectively, and detectrespective heights of the four portions of the vehicle's body 8 thatcorrespond to the four wheels 4, respectively; a running-state detectingdevice 222 that detects a running state of the vehicle; aheight-controlling-mode selecting switch 224 that is operable to selectone of a plurality of height controlling modes; a near-object detectingdevice 226 that detects an object near to the vehicle; an operationdetecting device 228 that detects an operation; a height-controlcommanding switch 230; a working-liquid-temperature sensor 232 thatdetects a temperature of the working liquid; an ignition switch 236; avoice recognizing device 237; a shift-position detecting device 238; aparking-brake switch 240; four door-courtesy-lamp switches 242 that areassociated with four doors 254 of the vehicle; a running-speed sensor243 that detects a running speed of the vehicle; and agetting-in-and-out detecting device 244.

The running-state detecting device 222 that detects the running state ofthe vehicle may be one including a longitudinal-direction accelerationsensor that detects a braking or driving state of the vehicle (i.e., adecelerating or accelerating state of the vehicle); or one including alateral-direction acceleration sensor that detects a turning state ofthe vehicle. However, the turning state of the vehicle may be detectedby a yaw-rate sensor, a steering-angle sensor, or the running-speedsensor 243.

The height-controlling-mode selecting switch 224 is operable by a driverto select a desired one of an automatic mode and a manual mode. In astate in which the automatic mode is selected, the body heights areautomatically changed when a predetermined condition is met, accordingto the predetermined condition met; and in a state in which the manualmode is selected, the body heights are changed according to a targetheight position indicated by the height-control commanding switch 230.

The near-object detecting device 226 detects whether an object (e.g.,luggage) is present in at least one predetermined area near to thevehicle. In the present embodiment, the near-object detecting device 226includes four clearance sonars 248 and a front-object detecting device249, as shown in FIGS. 2A and 2B.

The four clearance sonars 248 are provided in four corner portions ofthe vehicle, and each of the clearance sonars 248 utilizes a supersonicwave. Each of the clearance sonars 248 includes an emitter that emits asupersonic wave and a receiver that receives the supersonic wavereflected from an object, and detects, based on the received supersonicwave, a relative-positional relationship between the vehicle's body 8and the object, for example, judges whether an object is present in acorresponding one of four predetermined areas, R0, shown in FIG. 2A,detects a distance between a detected object and the each sonar 248itself, and/or detects time-wise changes of the detected distance.

The front-object detecting device 249 utilizes a laser beam or amillimeter wave, includes an emitter that emits a laser beam or the likeand a receiver that receives the laser beam reflected from an object,and detects, e.g., whether an object is present in a predetermined area,R1. The front-object detecting device 249 may be one that is used in,e.g. a cruising control known in the art. In this case, the front-objectdetecting device 249 can detect an object present in an area wider thanthe predetermined area R1 shown in FIG. 2A. However, in the presentembodiment, the area R1 is so predetermined as to be able to detectwhether an object is present in a direction in which the body 8 is movedin a body-height controlling operation.

Alternatively, the near-object detecting device 226 may be one includinga back or rear sonar that is provided in a rear portion of the vehicle.

Otherwise, the near-object detecting device 226 may be one including thefour door-courtesy-lamp switches 242 each of which detects opening andclosing of a corresponding one of the four doors 254. When each of thedoors 254 is opened or closed, a corresponding one of the switches 242changes its state. For example, when each door 254 is opened, acorresponding courtesy lamp, not shown, is turned on, and thecorresponding switch 242 is switched to an ON state thereof. When eachdoor 254 is switched from a closed state thereof to an opened statethereof, or when each door 254 is kept at the opened state, it can bejudged that there is a possibility that an object may be present near tothe vehicle, because a person may get in, or out of, the vehicle throughthe opened door 254.

Moreover, the near-object detecting device 226 may be one includingdoor-lock sensors. When one of door locks is unlocked, it can be judgedthat there is a possibility that an object may be present near to thevehicle because a person may get in, or out of, the vehicle. In thiscase, however, a degree of possibility, i.e., a probability that anobject may be present near to the vehicle is lower than that in theabove-described case where opening or closing of one of the four doors254 is detected.

The front-object detecting device 249 may not be one that is used in thecruising control, but may be a sensor that can detect whether an objectis present in the predetermined area R1 in front of the vehicle.

The operation detecting device 228 detects whether an operation is beingperformed by a person. In the present embodiment, the operationdetecting device 228 detects at least one of a gasoline feedingoperation as a sort of energy-source supplying operation, an oilchanging operation, a roof loading operation, a roof repairingoperation, and a vehicle washing operation. The gasoline feedingoperation can be detected by detecting an operation of a fuel-lid openermotor 256 that opens and closes a fuel lid 255. The operation of thefuel-lid opener motor 256 is detected by a motor-operation detectingportion 258 that detects whether an electric current is being suppliedto the opener motor 256.

The oil changing operation is detected by detecting whether a cap of anoil pan for an engine, not shown, is in an opened state. This isdetected by a cap-opened-state detecting portion 260.

When a roof carrier 262 is loaded with luggage, the body heights aremore or less decreased. Therefore, the roof loading operation can bedetected based on respective values detected by the four body-heightsensors 220. Meanwhile, the respective values detected by thebody-height sensors 220 change not only when the body heights arecontrolled, but also when a person gets in, or out of, the vehicle.Therefore, in the present embodiment, it is possible to judge that thereis a possibility that the roof loading operation is being performed, ifactual changes of the body heights do not correspond to respectivechanges of the body heights to be caused by respective operations of thefour body-height controlling actuators 120 under a condition that noperson who gets in, or out of, the vehicle is detected. Whether a persongets in, or out of, the vehicle can be detected by thegetting-in-and-out detecting device 244.

When the vehicle is washed, a liquid (e.g., water) is applied to thevehicle, so that a temperature of the vehicle is changed. Thistemperature change is greater than natural temperature changes caused bychanges of the environment around the vehicle. In addition, since theliquid is applied to only specific portions of the vehicle, thetemperature of the vehicle is frequently changed. Therefore, if thetemperature change of the vehicle is greater than the naturaltemperature changes caused by the changes of the environment, if thetemperature of the vehicle abruptly changes up or down to a certainvalue and then does not change from that value any more, or if thetemperature of the vehicle too frequently changes, it is possible tojudge that the vehicle washing operation is being performed. Atemperature of an outer surface of the vehicle's body 8 is detected byan outside-air-temperature sensor 264.

Thus, in the present embodiment, the operation detecting device 228includes at least one of the motor-operation detecting portion 258, thecap-opened-state detecting portion 260, the body-height sensors 220, andthe outside-air-temperature sensor 264.

The height-control commanding switch 230 is manually operable by thedriver, for selecting one of a height increasing command, a heightdecreasing command, and a height-control stopping command. For example,when the height-control stopping command is selected, the current heightcontrolling operation is immediately stopped.

The getting-in-and-out detecting device 244 includes at least one ofseat-belt buckle switches 266 each of which detects whether a seat beltis worn; seating sensors 268 each of which detects whether a person isseated on a seat; and the door courtesy lamp switches 242. If at leastone of (a) that a detection signal outputted by each of the seat-beltbuckle switches 266 does not change, (b) that a detection signaloutputted by each of the seating sensors 268 does not change, and (c)that each of the doors 254 is kept closed (i.e., that no doors 254 areopened or closed) is detected, it is possible to judge that no persongets in, or out of, the vehicle.

The informing device 210 informs, when it is judged that there is apossibility that an object may be present, during, or before, abody-height controlling operation, at least one of (a) that abody-height controlling operation is performed (i.e., a body-heightcontrolling operation is started, or a body-height controlling operationis being performed) and (b) that there is a possibility that an objectmay be present in a direction in which the vehicle's body 8 is moved.The informing device 210 may be one that directs the information towardoutside the vehicle and/or inside the vehicle. In addition, theinforming device 210 may be one that outputs the information in avisible manner and/or an audible manner. The informing device 210 thatdirects the information toward outside the vehicle may be an outsidelamp 270 (e.g., a fog lamp, a turn signal lamp, a stop lamp, or a headlamp) that is provided on the outer surface of the vehicle's body 8, ora horn 272. The informing device 210 that directs the information towardthe driver inside the vehicle may be an inside lamp 274 (e.g., a hazardlamp) that is provided on an instrument panel, or a speaker 276 of anaudio device that is provided in the room of the vehicle. The informingdevice 210 includes at least one of the outside lamp 270, the horn 272,the inside lamp 274, and the speaker 276.

A communication device 280 is connected to the I/O portion 208 of thesuspension ECU 200. The communication device 280 includes a signaltransmitting and receiving antenna 281, and can communicate with aportable controller 282 worn by the driver who may be present within apredetermined area around the vehicle. The portable controller 282includes a communication portion 284 including a signal transmitting andreceiving antenna; and a processing portion 286 essentially constitutedby a computer that stores identification information identifying thecontroller 282 itself and produces and transmits information to thecommunication device 280. The portable controller 282 additionallyincludes a plurality of operable portions each of which is manuallyoperable to transmit, with the identification information, acorresponding one of the height increasing command and the heightdecreasing command.

The communication device 280 judges, when it receives information,whether the information has been transmitted from the portablecontroller 282 to the vehicle, based on the identification informationcontained by the received information. When it is judged that theinformation has been transmitted from the portable controller 282 to thevehicle, the suspension ECU 200 starts a body-height controllingoperation corresponding to the command transmitted from the portablecontroller 282. However, even if the portable controller 282 may nottransmit any height controlling commands, the suspension ECU 200 maystart a body-height controlling operation (i.e., a body-heightdecreasing operation), if it is detected that the portable controller282 has entered the predetermined area.

A navigation system 290 is also connected to the I/O portion 208. Thesuspension ECU 200 can detect a current position of the vehicle based oninformation supplied from the navigation system 290.

The storing portion 206 stores various control programs including aheight controlling program represented by a flow chart shown in FIG. 4.

Next, there will be described an operation of the suspension systemconstructed as described above.

In the center cylinder 52, the control piston 56 receives respectiveforces corresponding to the respective liquid pressures in therespective liquid chambers 16 of the four suspension cylinders 10associated with the four wheels 4FL, 4FR, 4RL, 4RR. Each of the fourforces is equal to the product of a corresponding one of the four liquidpressures and an area of a surface that receives the correspondingliquid pressure. In a state in which the control piston 56 is keptstill, the four forces are balanced with each other.

When the vehicle's body 8 pitches, for example, when a distance betweenthe two front wheel holding devices 6 and the body 8 increases and adistance between the two rear wheel holding devices 6 and the body 8decreases (e.g., when the vehicle is abruptly accelerated), therespective liquid pressures in the respective liquid chambers 16 of thesuspension cylinders 10FL, 10FR associated with the two front wheels4FL, 4FR decrease, and the respective liquid pressures in the respectiveliquid chambers 16 of the suspension cylinders 10RL, 10RR associatedwith the two rear wheels 4RL, 4RR increase. Thus, the respective liquidpressures acting on respective outer pressure-receive surfaces S_(OL),S_(OR) of the two end pistons 58, 59 decrease, and the respective liquidpressures acting on respective inner pressure-receive surfaces S_(IL),S_(IR) of the two end pistons 58, 59 increase. In this case, the fourforces acting on the control piston 56 remain balanced with each other,so that the movement of the control piston 56 is restrained. Thus, thefour suspension cylinders 10 operate as if they were independent of eachother, extremely speaking, as if the center cylinder 52 were notprovided, and accordingly the pitching of the vehicle is effectivelyattenuated.

When the vehicle's body 8 rolls, for example, when a distance betweenthe two left wheel holding devices 6 and the body 8 increases and adistance between the two right wheel holding devices 6 and the body 8decreases (e.g., when the vehicle turns to the left), the respectiveliquid pressures in the respective liquid chambers 16 of the suspensioncylinders 10FL, 10RL associated with the two left wheels 4FL, 4RLdecrease, and the respective liquid pressures in the respective liquidchambers 16 of the suspension cylinders 10FR, 10RR associated with thetwo rear wheels 4FR, 4RR increase. Thus, the respective liquid pressuresacting on the outer and inner pressure-receive surfaces S_(OL), S_(IL)of the end piston 58 decrease, and the respective liquid pressuresacting on the outer and inner pressure-receive surfaces S_(OR), S_(IR)of the end piston 59 increase. If the four forces acting on the controlpiston 56 remain balanced with each other, the four suspension cylinders10 operate as if they were independent of each other, and accordinglythe rolling of the vehicle is effectively attenuated.

When a force is inputted from a road surface to one of the four wheels4FL, 4FR, 4RL, 4RR, for example, when a force is inputted to thesuspension cylinder 10FL corresponding to the front left wheel 4FL in adirection decrease a distance between the wheel 4FL and the body 8(e.g., when the wheel 4FL rides on a protrusion on the road surface),the respective liquid pressures in the respective liquid chambers 16 ofthe suspension cylinder 10FL and the suspension cylinder 10RR diagonallyopposed to the cylinder 10FL increase, and the respective liquidpressures in the respective liquid chambers 16 of the two othersuspension cylinders 10FR, 10RL decrease. Thus, the respective liquidpressures acting on the outer pressure-receive surface S_(OL) of the endpiston 58 and the inner pressure-receive surface S_(IR) of the endpiston 59 increase, and the respective liquid pressures acting on theinner pressure-receive surface S_(IL) of the end piston 58 and the outerpressure-receive surface S_(OR) of the end piston 59 decrease. Thus, thebalancing of the four forces acting on the control piston 56 is broken,and the control piston 56 is moved to the rightward direction in FIG. 1.Consequently the respective volumes of the outer liquid chamber 66 andthe inner liquid chamber 65 are increased; and the respective volumes ofthe outer liquid chamber 67 and the inner liquid chamber 64 aredecreased. Thus, the working liquid flows out of the suspensioncylinders 10FL, 10RR, and flows into the suspension cylinders 10FR,10RL. That is, the four suspension cylinders 10FL, 10FR, 10RL, 10RRoperate as if the two suspension cylinders 10FL, 10RR communicated withthe two suspension cylinders 10FR, 10RL via the center cylinder 52 andthe working liquid flowed from the former cylinders 10FL, 10RR to thelatter cylinders 10FR, 10RL.

The spring constant of each of the four suspension cylinders 10 can bechanged by controlling a corresponding one of the four spring-constantswitching valves 28.

When each spring-constant switching valve 28 is in a communication statethereof, the corresponding liquid chamber 16 is communicated with thecorresponding two accumulators 24, 26, and accordingly the correspondingsuspension cylinder 10 takes a smaller spring constant; and when eachspring-constant switching valve 28 is in a shut-off state thereof, thecorresponding liquid chamber 16 is communicated with the correspondinghigh-pressure accumulator 24 only and is shut off from the correspondinglow-pressure accumulator 26, and accordingly the correspondingsuspension cylinder 10 takes a greater spring constant.

When the suspension cylinder 10 takes the smaller spring constant, theworking liquid more easily flows into, and out of, the cylinder 10, sothat the cylinder 10 can more effectively damp a high-frequencyvibration and thereby improve a riding quality of the vehicle. On theother hand, when the suspension cylinder 10 takes the greater springconstant, the center cylinder 52 can exhibit a higher degree ofresponsiveness.

Therefore, in the present embodiment, when the vehicle runs on a normalroad surface, the suspension cylinders 10 are controlled to take thesmaller spring constant; and when the four wheels are needed to grip,with a great force, a road surface, e.g., when the vehicle runs on a badroad surface, the suspension cylinders 10 are controlled to take thegreater spring constant.

The damping characteristic of each of the four suspension cylinders 10is controlled by controlling a corresponding one of the variablerestrictors 30.

When the flow area of the individual passage 22 corresponding to each ofthe four suspension cylinders 10 is decreased by the correspondingvariable restrictor 30, the each suspension cylinder 10 becomes “hard”(i.e., the damping force produced by the each suspension cylinder 10 isincreased under a condition that a relative movement speed of thecorresponding wheel 4 and the body 8 relative to each other in avertical direction is not changed); and when the flow area of theindividual passage 22 is increased by the corresponding variablerestrictor 30, the each suspension cylinder 10 becomes “soft” (i.e., thedamping force of the each suspension cylinder 10 is decreased). Therespective hardness of the four suspension cylinders 10 are controlledaccording to a current state of a mode selecting switch that is operableby the driver. However, it is possible to control the respectivehardness of the four suspension cylinders 10 based on a runningcondition of the vehicle. In the present embodiment, when the vehicle isturning, or when the vehicle is being braked or driven (i.e.,decelerated or accelerated), the four suspension cylinders 10 arecontrolled to be hard, so that the running stability of the vehicle canbe prevented from being lowered.

When each of the four suspension cylinders 10 takes the greater springconstant, the working liquid less easily flows into, and out of, thecylinder 10. In this case, therefore, the changing of the dampingcharacteristic of the each suspension cylinder 10 is less effective.Thus, in the present embodiment, when each of the suspension cylinders10 takes the smaller spring constant, a corresponding one of thevariable restrictors 30 is controlled.

In the present embodiment, the four heights of the vehicle's body 8relative to the four wheels 4 can be individually controlled by theheight controlling device 74.

When the body height corresponding to the front left wheel 4FL iscontrolled, the corresponding body-height controlling actuator 120FL iscontrolled. When the body height corresponding to the front left wheel4FL, i.e., a distance between the front left wheel FL and a portion ofthe body 8 that corresponds to the wheel 4FL is increased, the pressurestorage control valve 90 is opened and the individual control valve110FL is also opened, so that the working liquid is supplied from thepressure storage accumulator 86 to the suspension cylinder 10FL. If anactual body height becomes equal to a target body height, the individualcontrol valve 110FL is closed. On the other hand, in the case where thepressure storage accumulator 86 does not store a sufficient amount ofthe working liquid, the pumping device 84 is operated, so that theworking liquid outputted by the pump 81 is supplied to the suspensioncylinder 10FL.

When the body height corresponding to the front left wheel 4FL isdecreased, the individual control valve 110FL is opened and the flow-outcontrol valve 106 is also opened, so that the working liquid flows fromthe suspension cylinder 10FL to the reservoir 78. If the actual bodyheight becomes equal to the target value, the individual control valve110FL is closed and the flow-out control valve 106 is also closed.

When the ignition switch 236 is in an ON state thereof, the pumpingdevice 84 is controlled such that the pressure of the working liquidstored by the pressure storage accumulator 86 falls in a predeterminedrange.

In addition, when the body height corresponding to the front left wheel4FL is controlled, the corresponding spring-constant switching valve28FL is closed, so that the working liquid cannot flow between theindividual passage 22FL and the low-pressure accumulator 26FL. Thus, thebody-height controlling operation can be performed in a shorter timeduration as compared with a state in which the spring-constant switchingvalve 28FL is open.

A body-height controlling operation can be performed at a high speed(i.e., a rate of change of a body height is high; hereinafter, referredto as the high-speed body-height controlling operation) or a low speed(i.e., a rate of change of a body height is low; hereinafter, referredto as the low-speed body-height controlling operation). When the runningspeed of the vehicle is lower than a reference speed at which thevehicle can be regarded as being stopped, and simultaneously when apredetermined high-speed-control needing condition is met, thehigh-speed body-height controlling operation is performed. It is judgedthat the predetermined high-speed-control needing condition has beenmet, (a) if the communication device 280 has received information fromthe portable controller 282, (b) if the height-control commanding switch230 has been operated in the manual mode, or (c) a predeterminedcondition has been met in the automatic mode.

When the high-speed body-height controlling operation is performed toincrease the body heights, the individual control valves 110 are opened(i.e., a duty ratio (=(duty time)/(duty time+off-duty time)) is equal to1); and when the high-speed body-height controlling operation isperformed to decrease the body heights, the individual control valves110 are opened (i.e., a duty ratio is equal to 1) and the flow-outcontrol valve 106 is also opened (i.e., a duty ratio is equal to 1).When the high-speed body-height controlling operation is performed, thepressure storage control valve 90 is opened and, optionally, the pumpingdevice 84 is operated.

When the low-speed body-height controlling operation is performed, theindividual control valves 110 may be subjected to a duty control (i.e.,a duty ratio is smaller than 1), or both the individual control valves110 and the flow-out control valve 106 may be subjected to the dutycontrol.

When the ignition switch 236 is in an OFF state thereof, generally, thebody heights are controlled to a standard body height so that thevehicle may have a good appearance. However, since it is more or lessdifficult for a person to get in the vehicle in the state in which thebody heights are kept to the standard height, the body heights areautomatically decreased when the communication device 280 receives, fromthe portable controller 282, the information representing thebody-height decreasing command. That is, the body 8 is moved in adirection to approach the wheel holding devices 6. Since the bodyheights are decreased at the high speed, the body-height controlling(i.e., decreasing) operation can be started when the communicationdevice 280 has surely received the information from the portablecontroller 282 (i.e., when the driver having the portable controller 282approaches closer to the vehicle). This body-height control can becalled a “welcome” control.

When the height-control commanding switch 230 is operated, in the manualmode, to a position corresponding to the body-height decreasing command,the body heights are decreased. In this case, it is desirable todecrease the body heights as quickly as possible, so that the bodyheights can approach the target height according to the driver'sintension.

If at least one of (a) a predetermined condition that the vehicle isstopped after running and then a parking brake is operated and (b) apredetermined condition that a shift lever has been moved from a drivingposition to a parking position is met in the automatic mode, the bodyheights are automatically decreased because it can be judged that thereis a possibility that a person may get out of the vehicle. Since thebody heights are kept to the standard height when the vehicle isrunning, the body heights need to be decreased to such a height assuringthat a person can easily get out of the vehicle. In this case, too, itis desirable to decrease the body heights as quickly as possible. Evenif the above-indicated condition may not be met within a predeterminedtime duration following stopping of the vehicle after running, the bodyheights are automatically decreased.

On the other hand, when the communication device 280 receives, from theportable controller 282, the information representing the body-heightincreasing command, or when the height-control commanding switch 230 isoperated, in the manual mode, to a position corresponding to thebody-height increasing command, the body heights are increased. That is,the body 8 is moved in a direction away from the wheel holding devices6. If at least one of (a) a predetermined condition that the ignitionswitch 236 has been switched from the OFF state to the ON state and (b)a predetermined condition that the shift lever has been moved from theparking position to the driving position is met in the automatic mode,the body heights are automatically increased at the high speed. That is,when a person gets in the vehicle, the body heights are once decreased,but before the vehicle starts running, the body heights are increased tothe standard height. Thus, it is desirable to increase the body heightsas quickly as possible. If the switching of the ignition switch 236and/or the shifting of the shift lever are/is not detected within apredetermined time duration after the body heights are decreased underthe above-described welcome control and the opening and closing of thedoor(s) 254 are detected, then the body heights are automaticallyincreased.

However, if a possibility that an object may be present in a directionof movement of the vehicle's body 8 is detected during a body-heightcontrolling operation, the body-height controlling operation may bestopped from further moving the body 8 in that direction, or may beperformed at a decreased speed, or the body 8 may be moved in adirection opposite to that direction. Alternatively, if theabove-indicated possibility is detected before a body-height controllingoperation is started, the body-height controlling operation may not bestarted. Thus, the body 8 or the object (e.g., luggage) can be preventedfrom being damaged.

The manner in which a possibility that an object may be present in adirection of movement of the vehicle's body 8 is detected will bedescribed later. Here, it is noted that a possibility that an object maybe present in a direction of movement of the body 8 may be simplyreferred to as the “possibility of presence of object”, in the followingdescription.

The height controlling program, shown in FIG. 4, is implemented at apredetermined periodic cycle.

First, at Step S1, the suspension ECU 200 judges, based on the signalsupplied from the running-speed sensor 243, whether the running speed ofthe vehicle is lower than a reference speed at which the vehicle can beregarded as being stopped. If a positive judgment is made at Step S1,the control of the ECU 200 goes to Step S2 to judge whether a high-speedbody-height control flag is set at an ON state thereof. If a negativejudgment is made at Step S2, the control of the ECU 200 goes to Step S3to judge whether there is a need to control the body heights at the highspeed, as described above. If a positive judgment is made at Step S3,the control goes to Step S4 to detect a possibility that an object maybe present in a direction of movement of the vehicle's body 8. Step S4is followed by Step S5 to judge whether the possibility has beendetected.

If a negative judgment is made at Step S5, the control goes to Step S6to set the high-speed body-height control flag to its ON state, and thento Step S7 to start a body-height controlling operation at the highspeed. Thus, the ECU 200 controls the body-height controlling actuators120 so that actual body heights approach a target body height. Theactual body heights are increased in some cases and are decreased inother cases. On the other hand, if a positive judgment is made at StepS5, that is, if the possibility has been detected, the ECU 200 skipsSteps S6 and S7, i.e., does not start a body-height controllingoperation.

On the other hand, if a negative judgment is made at Step S3, that is,if there is no need to control the body heights at the high speed, theECU 200 repeats Steps S1 through S3. Even if a positive judgment may bemade at Step S3, the ECU 200 repeats Steps S1 through S5, if a positivejudgment is made at Step S5, i.e., if the possibility has been detected.In either case, the ECU 200 does not start a body-height controllingoperation.

On the other hand, if a positive judgment is made at Step S2, that is,if the high-speed body-height control flag is set at its ON state, thecontrol goes to Steps S8 and S9 that are identical with Steps S4 and S5,respectively. At Step S8, the ECU 200 detect a possibility that anobject may be present in a direction of movement of the vehicle's body8, and Step S8 is followed by Step S9 to judge whether the possibilityhas been detected.

If a negative judgment is made at Step S9, the control goes to Step S10to detect actual body heights, and then to Step S11 to judge whether theactual body heights have reached the target body height. If a negativejudgment is made at Step S11, the control goes to Step S12 to judgewhether the ECU 200 has received the height-control stopping command. Ifa negative judgment is made at Step S12, the control goes to Step S13 tocontinue the current body-height controlling operation.

However, even if a negative judge may be made at Step S9, i.e., theremay be no possibility of presence of object, the current body-heightcontrolling operation is stopped if the height-control stopping commandis received from the height-control commanding switch 230. That is, ifthe driver operates the switch 230 in an emergency, the currentbody-height controlling operation can be immediately stopped.

Meanwhile, if a positive judgment is made at Step S11, the control goesto Step S14 to control the body-height controlling actuator 120 to endthe current body-height controlling operation, and then to Step S15 toreset the high-speed body-height control flag to an OFF state thereof.

If a positive judgment is made at Step S9, i.e., if it is judged thatthere is the possibility of presence of object, the control goes to StepS16 to judge whether an operation resuming condition has been met. Theoperation resuming condition is met if, in the case where a positivejudgment is made at Step S9 because one door 254 is switched from theclosed state to the opened state, the door 254 is switched from theopened state to the closed state before a predetermined time durationhas elapsed. If an actual time duration in which one door 254 is keptopened is shorter than the predetermined time duration, a degree ofpossibility that a person may get in, or out of, the vehicle isconsiderably low. In this case, therefore, it can be judged that noobjects are present around the vehicle and accordingly the body-heightcontrolling operation can be started again.

If a negative judgment is made at Step S16, the control goes to Step S17to restrain the movement of the vehicle's body 8. As will be describedlater, the ECU 200 controls the body-height controlling actuators 120 tostop the current body-height controlling operation (i.e., stop themovement of the vehicle's body 8), reverse the direction of the currentbody-height controlling operation (i.e., reverse the direction ofmovement of the body 8), or lower the speed of the current body-heightcontrolling operation (i.e., lower the speed of movement of the body 8).

For example, when the body heights are decreased at the high speed and,in this case, the direction of movement of the body 8 is reversed, it ispreferred that the individual control valves 110 be opened, the pressurestorage control valve 90 be opened, and the pumping device 84 beoperated such that the pump 81 outputs a maximum amount of the workingliquid. Consequently the direction of the current body-heightcontrolling operation can be reversed quickly, and the body heights canbe increased quickly.

In addition, when the body heights are decreased at the high speed and,in this case, the current body-height controlling operation (i.e., themovement of the body 8) is stopped, it is preferred that the individualcontrol valves 110 be switched to the closed state. However, if, in astate in which the individual control valves 110 are kept opened, thepumping device 84 is operated, or the pressure storage control valve 90is switched to the opened state, for a predetermined time duration, thedecreasing of the body height can be stopped quickly. In the lattercase, after the predetermined time duration has elapsed, the individualcontrol valves 110 are each switched to the closed state.

Decreasing of the speed of the body-height controlling operation can bedone by controlling the duty ratio of the individual control valves 110.

Step S17 is followed by Step S18 to operate the informing device 210,and then by Step S19 to judge whether the body-height controllingoperation is being performed at a decreased speed. If a positivejudgment is made at Step S19, the control goes to Step S10.

Meanwhile, if a positive judgment is made at Step S16, the control goesto Step S20 to resume the body-height controlling operation at thedecreased speed. In the present embodiment, the body-height controllingoperation is resumed at the same speed as a low speed at which thelow-speed body-height controlling operation is performed at Step S22,described later. To this end, the ECU 200 controls the duty ratio of theindividual control valves 110. Since Step S20 is carried out in thestate in which the high-speed body-height control flag is in the ONstate, the body-height controlling operation resumed at the decreasedspeed at Step S20 can be distinguished from the low-speed body-heightcontrolling operation performed at Step S22 when it is judged, at StepS21, that there is a need to control the body height at the low speed.

However, it is possible to perform the movement restraining control atStep S17 and/or the operation resuming control at Step S20, such thatthe body-height controlling operation is performed at a decreased speeddifferent from the low speed at which the low-speed body-heightcontrolling operation is performed at Step S22.

Once the high-speed body-height controlling operation is started, StepsS1, S2, and S8 through S15 are carried out if there is no possibility ofpresence of object, and Steps S1, S2, and S8 through S20 are carried outif there is the possibility of presence of object.

On the other hand, if a positive judgment is made at Step S1, that is,if the running speed of the vehicle is not lower than the referencespeed and the vehicle cannot be regarded as being stopped, the controlof the ECU 200 goes to Step S21 to judge whether there is a need tocontrol the body heights at the low speed. For example, in the casewhere the speed at which the vehicle is running on, e.g., an expresswayis not lower than the reference speed, a body-height controllingoperation is performed to decrease the body heights. This body-heightcontrolling operation is performed at the low speed.

In the present embodiment, a portion of the suspension ECU 200 thatstores and carries out Steps S2, S3, S6, S7, S14, and S15 constitutes ahigh-speed height control portion; and a portion of the suspension ECU200 that stores and carries out Steps S21 and S22 constitutes alow-speed height control portion.

The height-control commanding switch 230 may be provided on the portablecontroller 282. In addition, Step S12 may be modified such that the ECU200 judges whether the ECU 200 (or the voice recognizing device 237) hasdetected a voice meaning the height-control stopping command. In thismodified embodiment, if a positive judgment is made at Step S12, thecurrent body-height controlling operation is ended at Step S14.Moreover, Step S12 may be modified such that the ECU 200 judges whetherthe vehicle's body 8 has contacted an object. In this modifiedembodiment, if a positive judgment is made at Step S12, the currentbody-height controlling operation is ended at Step S14. Furthermore, itis possible to employ, in addition to the height-control commandingswitch 230, an exclusive switch that can be used in an emergency to stopthe current body-height controlling operation.

The above-described height controlling program may be implemented in anyof various manners employed by the following embodiments.

Embodiment 1

In this embodiment, at each of Steps S4 and S8, the near-objectdetecting device 226 detects an object that may be present in thepredetermined areas R0, R1 around the vehicle. Thus, the near-objectdetecting device 226 can detect the possibility of presence of object,not only before (Step S4), but also after (Step S8), a body-heightcontrolling operation is started. However, in Embodiment 1, Steps S16and S20 are omitted. That is, the suspension ECU 200 does not detect orjudge whether the operation resuming condition has been met.

If, before a body-height controlling operation is started, thenear-object detecting device 226 detects an object present in thepredetermined areas R0, R1 around the vehicle, the ECU 200 judges thatthere is a possibility that an object may be present in a direction ofmovement of the vehicle's body 8. Thus, a positive judgment is made atStep S5, and accordingly Steps S6 and S7 are not carried out, i.e., thebody-height controlling operation is not started.

If, after a body-height controlling operation is started, thenear-object detecting device 226 detects an object present in thepredetermined areas R0, R1 around the vehicle, a positive judgment ismade at Step S9, and the control of the ECU 200 goes to Step S17 toimmediately stop the current body-height controlling operation. However,if, in the state in which the current body-height controlling operationis stopped, the near-object detecting device 226 has changed not todetect any objects in the areas R0, R1, the positive judgment made atStep S9 changes to a negative judgment and accordingly the control ofthe ECU 200 goes to Step S10 and the following steps. At Step S13, thecurrent body-height controlling operation is continued and, if theactual body heights reach the target body height, i.e., if a positivejudgment is made at Step S11, then the current body-height controllingoperation is ended at Step S14.

In Embodiment 1, if, after the current body-height controlling operationis stopped, the near-object detecting device 226 has changed not todetect any objects in the areas R0, R1, then the current body-heightcontrolling operation is continued as it is. However, Embodiment 1 maybe modified such that once the current body-height controlling operationis stopped, the operation is not continued any more even if thenear-object detecting device 226 may change not to detect any objects inthe areas R0, R1.

Alternatively, Embodiment 1 may be modified such that when Step S13 iscarried out because, after the current body-height controlling operationis stopped, the near-object detecting device 226 changes not to detectany objects in the areas R0, R1, the current body-height controllingoperation is continued at a decreased speed.

Alternatively, Embodiment 1 may be modified such that before apredetermined time duration (i.e., a time limit) has elapsed since ahigh-speed body-height controlling operation is started at Step S7, thebody-height controlling actuators 120 are controlled depending uponwhether there is the possibility of presence of object but, if apositive judgment is made at Step S9 after the predetermined timeduration has elapsed, the high-speed body-height controlling operationis unconditionally ended at Step S14. In this modified embodiment, thepredetermined time duration, i.e., the time limit is employed because itis not desirable to continue the high-speed body-height controllingoperation for too long a time duration.

In Embodiment 1, when the near-object detecting device 226 detects anobject in the areas R0, R1, the body-height controlling operation isstopped. However, it is possible to detect a relative-positionalrelationship between an object in the areas R0, R1 and the vehicle'sbody 8 and controls, based on the detected relationship, the body-heightcontrolling actuators 120.

For example, it is possible to detect a distance between an object andthe vehicle's body 8 (e.g., a main portion of each of the clearancesonars 248 or a main portion of the front-object detecting device 249)and controls, based on the detected distance, an appropriate one or onesof the body-height controlling actuators 120. More specificallydescribed, (i) since it can be judged that a probability that an objectmay be present in a direction of movement of the body 8 is lower whenthe detected distance is great than when the detected distance is small,Step S17 may be carried out such that a body-height controllingoperation is performed at a lower speed when the probability is highthan when the probability is low; and (ii) if the detected distance, D,is equal to, or smaller than, a reference distance, Ds (i.e., D≦Ds) andaccordingly it can be judged that a probability that an object may bepresent is high, a direction of a body-height controlling operation maybe reversed and, if the detected distance D is greater than thereference distance Ds (i.e., D>Ds) and accordingly it can be judged thatthe probability is low, a body-height controlling operation may bestopped.

Alternatively, it is possible to detect a direction of change of adistance between an object and the body 8 and controls, based on thedetected direction, an appropriate one or ones of the body-heightcontrolling actuators 120. For example, each body-height controllingactuator 120 may be controlled in three different manners correspondingto a first case where the distance between the object and the body 8decreases (i.e., the object approaches the body 8), a second case wherethe distance increases (i.e., the object moves away from the body 8),and a third case where the distance does not substantially change.

FIG. 5 shows a flow chart representing an object-presence-possibilitydetecting routine that may be implemented at each of Steps S4 and S8 ofFIG. 4. First, at Step S51, the suspension ECU 200 judges whether thenear-object detecting device 226 has detected an object present in thepredetermined areas R0, R1 around the vehicle. If a negative judgment ismade at Step S51, the control of the ECU 200 goes to Step S52 to judgethat there is no possibility of presence of object. On the other hand,if a positive judgment is made at Step S51, the control goes to Step S53to determine a time-wise change, dD/dt, of the distance D between thedetected object and the vehicle's body 8. Step S53 is followed by StepS54 to judge whether the detected object is approaching the body 8. Ifthe determined change dD/dt is smaller than zero, i.e., dD/dt<0, i.e.,if the distance is decreasing, a positive judgment is made at Step S54and accordingly the control goes to Step S55 to judge that a degree ofpossibility, i.e., a probability that an object may be present in adirection of movement of the body 8 is high. On the other hand, if anegative judgment is made at Step S54, the control goes to Step S56 tojudge whether the detected object is moving away from the body 8. If thedetected change dD/dt is greater than zero, i.e., dD/dt>0, i.e., if thedistance is increasing, a positive judgment is made at Step S56 andaccordingly the control goes to Step S57 to judge that the probabilityis low. On the other hand, if a negative judgment is made at Step S56,the control goes to Step S58 to judge that the probability is medium.

FIG. 6 shows a flow chart representing a body-movement restrainingroutine that may be implemented at Step S17 of FIG. 4. First, at StepS61, the suspension ECU 200 judges whether the probability that anobject may be present in the direction of movement of the body 8 ishigh. If a positive judgment is made at Step S61, the control goes toStep S62 to control the body-height controlling actuators 120 to reversea direction of the current body-height controlling operation, so thatthe body 8 is moved away from the detected object. If a negativejudgment is made at Step S61, the control goes to Step S63 to judgewhether the probability is low. If a negative judgment is made at StepS63, the control goes to Step S64 to control the body-height controllingactuators 120 to stop the current body-height controlling operation, sothat the body 8 is not moved any more. If a positive judgment is made atStep S63, the control goes to Step S65 to control the body-heightcontrolling actuators 120 to perform the current body-height controllingoperation at a decreased speed, so that the body 8 is moved at thedecreased speed. In the last case, the speed of the current high-speedbody-height controlling operation is decreased to the same speed (i.e.,a predetermined speed) as the low speed at which the low-speedbody-height controlling operation is performed at Step S22.

The informing device 210 may be operated in three different mannerscorresponding to the three different probabilities, i.e., threedifferent degrees of possibility of presence of object.

FIG. 7 shows a flow chart representing an informing-device operatingroutine that may be implemented at Step S18 of FIG. 4. First, at StepS71, the suspension ECU 200 judges whether the probability that anobject may be present in the direction of movement of the body 8 ishigh. If a positive judgment is made at Step S71, the control goes toStep S72 to control the inside and outside lamps 274, 270 to flicker andadditionally control the speaker 276 and the horn 272 to generatesounds. That is, the informing device 210 can inform not only one ormore persons inside the vehicle but also one or more persons outside thevehicle, of the fact that the probability is high. Thus, the driver canoperate the height-control commanding switch 230 so as to stop thebody-height controlling operation. If a person is present outside thevehicle, that person can move the object away from the vehicle.

On the other hand, if a negative judgment is made at Step S71, thecontrol goes to Step S73 to judge whether the probability is low. If apositive judgment is made at Step S73, the control goes to Step S74 tocontrol only the inside lamp 274 to flicker and thereby inform thedriver of the fact that the probability is low. When the probability islow, it is not so highly needed to inform a person outside the vehicle,of the fact. On the other hand, if a negative judgment is made at StepS73, i.e., if the probability is medium, the control goes to Step S75 tocontrol the lamps 270, 274 to flicker but not to control the speaker 276or the horn 272. That is, the informing device 210 informs respectivepersons inside and outside the vehicle, of the fact, in the visiblemanner only. Since the informing device 210 is operated in the differentmanners corresponding to the different degrees of possibility ofpresence of object, the driver inside the vehicle and/or one or morepersons outside the vehicle can be informed, as needed, of thepossibility of presence of object.

The informing device 210 may be operated when the vehicle has failed.Therefore, when the informing device 210 is operated at Step S18, it isdesirable that the device 210 be operated in a different manner than themanner in which the device 210 is operated upon failure of the vehicle.

The manner in which the possibility of presence of object is detected atStep S4 and the manner in which the possibility is detected at Step S8may differ from each other. For example, at Step S4, whether an objectis present in the predetermined areas R0, R1 may be detected and, atStep S8, a degree of possibility of presence of an object may bedetected based on a relative-positional relationship between the objectand the vehicle's body 8. Alternatively, at Step S4, it may be judgedthat there is no possibility of presence of an object, if the object ismoving away from the body 8. When an object is moving away from the body8, it can be judged that a body-height controlling operation can besafely started.

Otherwise, the body-height controlling actuators 120 may be controlledbased on an amount of change of the distance between the vehicle's body8 and an object, i.e., a speed of relative movement between the body 8and the object.

FIG. 8 shows a flow chart representing anotherobject-presence-possibility detecting routine that may be implemented ateach of Steps S4 and S8 of FIG. 4. The flow chart of FIG. 8 includes, inaddition to Steps S51 through S58 of FIG. 5, Steps S81 and S82. If apositive judgment is made at Step S54, the control of the suspension ECU200 goes to Step S81 to judge whether an absolute value of the speed,|dD/dt |, at which the object is approaching the body 8 is higher than areference speed, V₁. If a positive judgment is made at Step S81 (i.e.,|dD/dt|>V₁), the control goes to Step S55 to judge that a probabilitythat an object may be present is high. On the other hand, if a negativejudgment is made at Step S81 (i.e., |dD/dt|≦V₁), or if a negativejudgment is made at Step S56, i.e., the object is not approaching thebody 8 or moving away from the same 8 (i.e., dD/dt≈0), the control goesto Step S55 to judge that the probability is medium. On the other hand,if a positive judgment is made at Step S56, the control goes to Step S82to judge whether the speed |dD/dt| at which the object is moving awayfrom the body 8 is higher than a reference speed, V₂. If a positivejudgment is made at Step S82 (i.e., |dD/dt|>V₂), the control goes toStep S52 to judge that there is no possibility of presence of object. Onthe other hand, if a negative judgment is made at Step S82, the controlgoes to Step S57 to judge that the probability is low.

In this modified embodiment, the probability or degree of possibility ofpresence of object can be more finely detected.

The reference speeds V₁, V₂, employed at Steps S81 and S82, may be equalto, or different from, each other.

Otherwise, two or more of the distance between the body 8 and theobject, the direction of change of the distance, and the amount ofchange of the distance may be used in combination so as to detect thepossibility of presence of object and control, based on the detectedpossibility, the body-height controlling actuators 120 and/or theinforming device 210. Moreover, the possibility may be detected based ona value obtained by differentiating, n times (n≧1), the amount of changeof the distance (i.e., the speed of relative movement between the body 8and the object).

Otherwise, it is possible to obtain an object-presence-possibilityvalue, X, based on a relative-positional relationship between thevehicle's body 8 and an object present in the predetermined areas R0, R1and control, based on the obtained possibility value X, the body-heightcontrolling actuators 120. The possibility value X may be defined by thefollowing expression, i.e., mathematical function:

X=f(L,V,Z,α)

-   -   where L is the distance between the object present in the areas        R0, R1 and the body 8; V is a speed of movement of the object; Z        is a value indicating whether the object is approaching, or        moving away from, the body 8 (e.g., Z=1 indicates that the        object is approaching and Z=0 indicates that the object is        moving away); and α is one or more other parameters.

A greater possibility value X indicates that a probability that anobject may be present in a direction of movement of the body 8 ishigher, than a smaller probability value X. The possibility value X isgreater when the distance L is small than when the distance L is great,and the possibility value X is greater when the object is approachingthan when the object is moving away.

Thus, at each of Steps S4 and S8, the suspension ECU 200 may detect thepossibility of presence of object, if the possibility value X is greaterthan a judging threshold, W, (i.e., X>W), and may judge that there is nopossibility of presence of object, if the value X is not greater thanthe judging threshold W (i.e. X≦W).

Possibility values X may be classified into three or more ranges, so asto evaluate a degree of possibility of presence of object.

For example, at each of Steps S4 and S8, it can be judged that when thepossibility value X is greater than a first judging threshold, W₁,(i.e., X>W₁), a degree of possibility of presence of object is high,that when the possibility value X is not greater than the first judgingthreshold W₁ (i.e., X≦W₁) and is greater than a second judgingthreshold, W₂, smaller than the first threshold W₁ (i.e., X>W₂), thedegree of possibility, i.e., probability is medium, and that when thepossibility value X is not greater than the second judging threshold W₂(i.e., X≦W₂), the probability is low.

At Step S17, the body-height controlling actuators 120 may be operatedin different manners corresponding to the different degrees ofpossibility of presence of object; and at Step S18, the informing device210 may be operated in different manners corresponding to the differentdegrees of possibility of presence of object.

Possibility values X may not be used as they are. For example, a degreeof necessity to stop a current body-height controlling operation and/ora degree of necessity to change a manner in which a current body-heightcontrolling operation is performed, may be evaluated based on one ormore possibility values X.

In Embodiment 1, the near-object detecting device 226 and a portion ofthe suspension ECU 200 that stores and implements Steps S4 and S8 of thebody-height controlling program cooperate with each other to constitutea near-object detecting portion as a possibility detecting device; and aportion of the ECU 200 that stores and implements Step S17 andadditionally Step S5 (more specifically described, the manner in whichwhen a positive judgment is made at Step S5, Steps S6 and S7 are notimplemented) constitutes a near-object-detection-related actuatorcontrol portion as a movement restraining portion.

The near-object detecting portion also functions as an object-in-areadetecting portion, a relative-positional-relationship detecting portion,or a possibility-degree detecting portion. A portion of the near-objectdetecting portion that stores and implements Steps S53 through S58constitutes the possibility-degree detecting portion. A portion of thenear-object-detection-related actuator control portion that stores andimplements Step S64 constitutes a height-control stopping portion; aportion of the near-object-detection-related actuator control portionthat stores and implements Step S62 constitutes a direction reversingportion; a portion of the near-object-detection-related actuator controlportion that stores and implements Step S65 constitutes aheight-control-speed decreasing portion; and a portion of thenear-object-detection-related actuator control portion that stores andimplements Steps S61 through S65 constitutes apossibility-degree-dependent actuator control portion. Theheight-control stopping portion also functions as ahigh-speed-height-control stopping portion.

Embodiment 2

In this embodiment, at each of Steps S4 and S8, the operation detectingdevice 228 detects the possibility of presence of object. When theoperation detecting device 228 detects a pre-selected sort of operation,it can be judged that there is a possibility that an object may bepresent in a direction of movement of the vehicle's body 8. Therefore,if the operation detecting device 228 detects a pre-selected operationbefore a body-height controlling operation is started, a positivejudgment is made at Step S5 and accordingly the body-height controllingoperation is not started. Meanwhile, if the operation detecting device228 detects a pre-selected operation after a body-height controllingoperation is started, a positive judgment is made at Step S9 andaccordingly the current body-height controlling operation is stopped. Inthe latter case, the detected pre-selected operation can be preventedfrom being adversely influenced by the changing of the body heights. InEmbodiment 2, too, Steps S16 and S20 are omitted, i.e., whether theoperation resuming condition has been met is not judged by thesuspension ECU 200.

For example, when the fuel lid opener motor 256 is operated to open thefuel lid 255, the suspension ECU 200 judges that a preparing operationfor a fueling operation is being performed; and if, thereafter, themotor 256 is not operated, the ECU 200 judges that the fueling operationis being performed. Meanwhile, when the motor 256 is operated to closethe fuel lid 255, the ECU 200 judges that an ending operation for thefueling operation is being performed.

Regarding a vehicle which does not employ the fuel lid opener motor 256,it is possible to provide the fuel lid 255 with a contact switch, so asto detect whether the fuel lid 255 is open or closed, and thereby detectwhether the fueling operation is being performed. Alternatively, it ispossible to judge that the fueling operation is being performed, when anamount of the fuel present in a fuel tank is increasing.

When the cap of the oil pan is changed from the closed state to theopened state, the ECU 200 judges that an oil changing operation has beenstarted; when the cap is kept opened, the ECU 200 judges that the oilchanging operation is being performed; and when the cap is changed fromthe opened state to the closed state, the ECU 200 judges that the oilchanging operation has been ended.

In a state in which the get-in-and-out detecting device 224 does notdetect any persons who get in, or out of, the vehicle and a body-heightcontrolling operation is not performed, the suspension ECU 200 can judgethat a roof-carrier loading operation is being performed, if thebody-height sensors 220 detect that the body heights have decreased bymore than a predetermined amount and/or that the body heights are keptto the decreased height. The roof-carrier loading operation is anoperation to load the roof carrier 262 with luggage.

During a body-height controlling operation, the suspension ECU 200 mayjudge that the roof-carrier loading operation is being performed, ifactual body heights significantly differ from a nominal body heightcorresponding to a specific manner in which the body-height controllingactuators 120 are controlled, or if a mode (e.g., a rate) of change ofactual body heights significantly differ from a mode of change of anominal body height corresponding to a specific manner of controlling ofthe body-height controlling actuators 120.

However, the roof-carrier loading operation may be detected withoutusing the respective values detected by the body-height sensors 220. Forexample, it is possible to provide fixing jigs of the roof carrier 262with contact switches and detect, based on respective changes ofrespective detection signals produced by the contact switches, whetherthe roof carrier 262 is loaded with luggage.

When the outside air temperature has changed by more than a usual changeamount, or when the temperature changes significantly frequently, thesuspension ECU 200 judges that a vehicle washing operation is beingperformed.

When a pre-selected operation is performed at an exclusive place, thesuspension ECU 200 can judge that the pre-selected operation is beingperformed, based on information supplied from the navigation system 290.For example, when the navigation system 290 detects that the vehicle isnow stopped at a gasoline stand, then the ECU 200 can judge that afueling operation is being performed; when the navigation system 290detects that the vehicle is stopped at a repair shop or a dealer shop,then the ECU 200 can judge that an oil changing operation is beingperformed; and when the navigation system 290 detects that the vehicleis stopped at a washing place, then the ECU 200 can judge that a vehiclewashing operation is being performed.

In Embodiment 2, the operation detecting device 228 and a portion of thesuspension ECU 200 that stores and implements Steps S4 and S8 cooperatewith each other to constitute an operation detecting portion.

Embodiment 3

In this embodiment, at each of Steps S4 and S8, the suspension ECU 200detects whether there is a possibility that an object may be present,based on whether each one of the four doors 254 is opened or closed,i.e., the respective detection signals supplied from the four doorcourtesy lamp switches 242. When any one of the doors 254 is changedfrom its closed state to its opened state, or when any door 254 is keptto the opened state, it can be judged that a person may get out of, orin, the vehicle and accordingly an object such as luggage may be presentaround the vehicle. If the above-indicated possibility is detectedbefore a body-height controlling operation is started, the operation isnot started; and if the possibility is detected after the operation isstarted, the current operation is stopped at Step S17.

Meanwhile, when any door 254 is changed from its opened state to itsclosed state after the door 254 is kept to the opened state for a timeduration shorter than a predetermined time duration, the ECU 200 judges,at Step S16, a positive judgment, i.e., that the operation resumingcondition has been met. Since the time duration in which the door 254 iskept to the opened state before it is changed to the closed state issufficiently short, it can be judged that a probability that a personmay get out of the vehicle is considerably low.

If a positive judgment is made at Step S16, the control of the ECU 200goes to Step S20 to resume the body-height controlling operation, but,at a speed lower than a speed before the resumption, because apossibility that an object may be present in a direction of movement ofthe body 8 cannot completely be negated.

A predetermined conditions that are employed, at each of Steps S4 andS8, to judge that any door 254 has been changed to its opened state mayadditionally include a condition that the position of the shift lever,detected by the shift-position detecting device 238, is changed from thedriving (D) position to the parking (P) position and/or a condition thatthe parking brake switch 240 is changed from its OFF state to its ONstate. If those conditions are met, a probability that a person may getout of the vehicle after the vehicle is changed from its running stateto its parking state is increased. Those conditions may additionallyinclude a condition that the ignition switch 236 is changed from its ONstate to its OFF state.

When a negative judgment is made at Step S16, e.g., the time duration inwhich the door 254 is kept to its opened state is not shorter than thepredetermined time duration, it can be judged that a probability that anobject may be present is higher than that when the time duration isshorter. That is, when the time duration in which the door 254 is keptto its opened state is sufficiently short, a probability that no personhas got in, or out of, the vehicle is high; but when the time durationis long, a probability that a person has got in, or out of, the vehicleis high.

However, Step S20 may be modified such that the body-height controllingoperation is resumed at the same speed as that before the resumption.

In Embodiment 3, the door courtesy lamp switches 242 and a portion ofthe suspension ECU 200 that stores and implements Steps S4 and S8constitutes a door-state detecting portion; and a portion of thesuspension ECU 200 that stores and implements Steps S16 and S20constitutes an operation resuming portion.

The suspension ECU 200 may detect the possibility of presence of object,based on the respective detection results of two or more of thenear-object detecting device 226, the operation detecting device 228,and the door courtesy lamp switches 242. For example, when thenear-object detecting device 226 detects that an object is present inthe predetermined areas R0, R1 and simultaneously when the operationdetecting device 228 detects that a pre-selected operation is beingperformed and/or when at least one of the door courtesy lamp switches242 detects that a corresponding one of the doors 254 is in its openedstate, the ECU 200 may judge that there is a possibility that an objectmay be present in a direction of movement of the body 8.

Alternatively, when at least two conditions out of (a) a first conditionthat the near-object detecting device 226 detects that an object ispresent in the areas R0, R1, (b) a second condition that the operationdetecting device 228 detects that a pre-selected operation is beingperformed, and (c) a third condition that at least one of the doorcourtesy lamp switches 242 detects that a corresponding one of the doors254 is in its opened state are met, the suspension ECU 200 may judgethat a probability that an object may be present is high; and when onlyone of the three conditions (a), (b), (c) is met, the ECU 200 may judgethat the probability is low. For example, when the first condition (a)and the second and/or third conditions (b), (c) are met, the ECU 200 mayjudge that the probability is high; and when only the first condition(a) is met, the ECU 200 may judge that the probability is low.

Otherwise, when at least one of the above-described three conditions(a), (b), (c) is met, the suspension ECU 200 may judge that there is apossibility that an object may be present in a direction of movement ofthe body 8. In the last case, even if the operation detected by theoperation detecting device 228 may have been finished, a positivejudgment is made at Step S5 or Step S9 so long as the near-objectdetecting device 226 detects that an object is present in the areas R0,R1.

In each of Embodiments 1, 2, and 3, the suspension ECU 200 judges, whenan object is present near to the vehicle, that there is a possibilitythat an object may be present in a direction of movement of the body 8,and thereby restrains a body-height controlling operation. However, aswill be described below, the ECU 200 may detect, based on respectivechanges of respective relative-positional relationships between the body8 and the four wheels 4, i.e., respective changes of the four bodyheights, whether there is a possibility that an object may be present ina direction of movement of the body 8, and thereby restrains abody-height controlling operation. In each of Embodiments 1, 2, and 3,the ECU 200 detects the possibility of presence of object, both beforeand after a body-height controlling operation is started. On the otherhand, in each of the following embodiments, the ECU 200 cannot detectthe possibility before a body-height controlling operation is started.Thus, Steps S4 and S5 are omitted from the flow chart of FIG. 4. Inaddition, Steps S16 and S20 are omitted since the ECU 200 does not judgethat the operation resuming condition has been met.

Embodiment 4

When a body-height controlling operation is performed, basically, thefour body-height controlling actuators 120 are controlled to change, ata same speed, the four body heights, respectively. For example, when ahigh-speed body-height controlling operation is performed, the four bodyheights are changed at a predetermined high speed, V_(H). To this end,each of the four individual control valves 110 is kept to its openedstate, so that an acceleration of change of a corresponding one of thefour body heights may be equal to zero.

Hence, in Embodiment 4, at Step S8, the suspension ECU 200 judgeswhether a speed, V, of change of at least one of the four body heightscorresponding to the four wheels 4 is lower than an abnormality judgingthreshold value, V_(th). The four body heights are detected by the fourbody-height sensors 220, respectively.

When the change speed V is smaller than the threshold value V_(th)(i.e., V<V_(th)), the ECU 200 makes, at step S9, a positive judgment,i.e., that there is a possibility that an object may be present in adirection of movement of the vehicle's body 8.

When a positive judgment is made at Step S9, the control of the ECU 200goes to Step S17 to stop the current body-height controlling operation,reverse the direction of the body-height controlling operation, i.e.,the direction of movement of the body 8, or decrease the speed of thebody-height controlling operation, i.e., the speed of movement of thebody 8.

The abnormality judging threshold value V_(th) may be a value smallerthan the predetermined high speed V_(H) by more than a predeterminedamount, or a value obtained by multiplying the high speed V_(H) by avalue smaller than 1. A common value as the high speed V_(H) may be usedboth in the case where the body heights are increased and in the casewhere the body heights are decreased, or different values as the highspeed V_(H) may be used in the two cases, respectively.

At Step S8, the suspension ECU 200 may judge whether an acceleration, G,of change of at least one of the four body heights is smaller than apredetermined acceleration value (i.e., whether the change accelerationG has changed from 0 to a value smaller than the predeterminedacceleration value).

When the change acceleration G is smaller than an abnormality judgingthreshold value, G_(th) (i.e., G<G_(th)), the ECU 200 makes, at step S9,a positive judgment, i.e., that there is a possibility that an objectmay be present.

Alternatively, at Step S8, the suspension ECU 200 may judge whether thechange speed V is lower than the abnormality judging threshold speedV_(th) and simultaneously judge whether the change acceleration G issmaller than the abnormality judging threshold acceleration G_(th). Inthis case, if the following conditions: V<V_(th) and G<G_(th) are met,then the ECU 200 makes, at step S9, a positive judgment, i.e., thatthere is a possibility that an object may be present.

Otherwise, at Step S8, the suspension ECU 200 may judge whether adifferentiated value, dG, of the change acceleration G is smaller thanan abnormality judging threshold value, dG_(th). In this case, if thefollowing condition: dG<dG_(th) is met, then the ECU 200 makes, at stepS9, that there is a possibility that an object may be present.

Based on the differentiated value dG of the change acceleration G, theECU 200 can detect the possibility of presence of object more quicklythan based on the change speed V or the change acceleration G.

In Embodiment 4, the body-height sensors 220 and a portion of thesuspension ECU 200 that stores and implements Step S8 constitutes aheight-change-dependent possibility detecting portion; and a portion ofthe suspension ECU 200 that stores and implements Step S17 constitutes aheight-change-dependent actuator control portion. Theheight-change-dependent possibility detecting portion also functions asa change-speed-related-amount-dependent possibility detecting portion.

Embodiment 5

When a body-height controlling operation is performed, all the fourindividual control valves 110 corresponding to the four wheels 4,respectively, are controlled in a same manner. Therefore, the suspensionECU 200 can detect whether there is a possibility that an object may bepresent, by comparing respective relative-positional relationshipsbetween the body 8 and the four wheels 4, with each other.

In Embodiment 5, at Step S8, the suspension ECU 200 obtains respectivedifferentiated values dG of the respective change accelerations G of thefour body heights corresponding to the four wheels 4. The four bodyheights are detected by the four body-height sensors 220, respectively.The thus obtained four differentiated values dG include the smallestvalue, dG_(min), the second smallest value, dG_(midL), the secondgreatest value, dG_(midH), and the greatest value, dG_(max). When anabsolute value, |ΔdG|, of a difference, (dG_(min)−dG_(midL)), of thesmallest value dG_(min) and the second smallest value dG_(midL) is equalto, or greater than, an abnormality judging threshold value, ΔdGs (i.e.,|ΔdG|≧ΔdGs), the ECU 200 makes, at step S9, that there is a possibilitythat an object may be present. The abnormality judging threshold valueΔdGs may be a default value, or a value determined based on the smallestvalue dG_(min) (i.e., ΔdGs=N·ΔdGs; N is a coefficient).

In this case, the ECU 200 can judge, with respect to each one of thefour wheels 4, that there is a possibility that an object may be presentin a direction of movement of the body 8, or can judge that there is apossibility that an object may be present in a direction of movement ofa portion of the body 8 that is opposed to the wheel 4 corresponding tothe smallest value dG_(min).

FIG. 9 shows a flow chart representing an object-presence-possibilitydetecting routine that is implemented at Step S8.

At Step S101, the suspension ECU 200 obtains, with respect to each ofthe four wheels 4 (4FL, 4FR, 4RL, 4RR), a differentiated value dG_(ij)(i=F, R, j=L, R) of the change acceleration G of a corresponding one ofthe four body heights. Then, at Step S102, the ECU 200 selects, from thethus obtained four differentiated values dG, the smallest value dG_(min)and the second smallest value dG_(midL). Subsequently, at Step S103, theECU 200 judges whether an absolute value |ΔdG| of a difference(dG_(min)−dG_(midL)) of the smallest value dG_(min) and the secondsmallest value dG_(midL) is equal to, or greater than, an abnormalityjudging threshold value ΔdGs.

If a positive judgment is made at Step S103 (i.e., |ΔdG|≧ΔdGs), thecontrol of the ECU 200 goes to Step S104 to judge that there is apossibility that an object may be present in a direction of movement ofa portion of the body 8 that is opposed to the wheel 4 corresponding tothe smallest value dG_(min). On the other hand, if a negative judgmentis made at Step S103 (i.e., |ΔdG|<ΔdGs), the control goes to Step S105to judge that all the four differentiated values dG corresponding to thefour wheels 4 are normal, i.e., that there is no possibility that anobject may be present. Since the smallest value dG_(min) is normal, itcan be judged that all the differentiated values dG are normal.

In a modified form of Embodiment 5, at Step S102, the ECU 200 selectsthe second smallest value dG_(midL) and the second greatest valuedG_(midH) and, at Step S103, the ECU 200 judges whether an absolutevalue |ΔdG| of a difference (dG_(midL)−dG_(midH)) of the second smallestvalue dG_(midL) and the second greatest value dG_(midH) is equal to, orgreater than, an abnormality judging threshold value ΔdGs.

In this modified form, if a positive judgment is made at Step S103, thecontrol goes to Step S104 to judge that there is a possibility that anobject may be present in a direction of movement of each of two portionsof the body 8 that are opposed to the two wheels 4 corresponding to thesmallest value dG_(min) and the second smallest value dG_(midL). Thoughthe smallest value dG_(min) is not compared with any threshold values,it can be judged that there is a possibility that an object may bepresent in a direction of movement of a portion of the body 8 that isopposed to the wheel 4 corresponding to the smallest value dG_(min). Inthis modified form, the abnormality judging threshold value ΔdGs may bea default value, or a value determined based on the second smallestvalue dG_(midL) (ΔdGs=N·ΔdGs; N is a coefficient).

In general, if two or more of the four differentiated values dG areabnormal, it can be speculated that the smallest value dG_(min) and thesecond smallest value dG_(midL) would be abnormal. In this case, if thesmallest value dG_(min) and the second smallest value dG_(midL) arecompared with each other, a difference of the two values dG_(min),dG_(midL) would be so small and accordingly each of the two values wouldbe judged as being normal. To avoid this, it is possible to judgewhether a difference of two next values of the four differentiatedvalues dG (dG_(min), dG_(midL), dG_(midH), dG_(max)) is equal to, orgreater than, an abnormality judging threshold value ΔdGs. In this case,if it is judged that the difference is smaller than the threshold valueΔdGs, then it can be judged that the value or all the values dG that isor are not greater than the smaller one of the two next values is or areabnormal.

In Embodiment 5, a portion of the suspension ECU 200 that stores andimplements Steps S101 through S105 constitutes adifferentiated-acceleration-dependent possibility detecting portion.

In another modified form of Embodiment 5, the suspension ECU 200 judges,with respect to each of the four wheels 4 (4FL, 4FR, 4RL, 4RR), thepossibility of presence of object, based on a change speed V_(ij) (i=F,R, j=L, R) of a corresponding one of the four body heights, according toa flow chart shown in FIG. 9B. More specifically described, at StepS181, the ECU 200 obtains, with respect to each of the four wheels 4, achange speed V_(ij) of a corresponding one of the four body heights.Then, at Step S182, the ECU 200 selects, from the thus obtained fourchange speed values V, the smallest value V_(min). Subsequently, at StepS183, the ECU 200 judges whether the smallest value V_(min) is smallerthan an abnormality judging threshold value, V_(minth). If a positivejudgment is made at Step S183, the control of the ECU 200 goes to StepS184 to judge that there is a possibility that an object may be presentin a direction of movement of a portion of the body 8 that is opposed tothe wheel 4 corresponding to the smallest value V. On the other hand, ifa negative judgment is made at Step S183, the control goes to Step S185to judge that all the four speed values V corresponding to the fourwheels 4 are normal, i.e., that there is no possibility that an objectmay be present. Since the smallest value V_(min) is normal, it can bejudged that all the speed values V are normal.

In another modified form of Embodiment 5, at Step S191 of FIG. 9C, thesuspension ECU 200 obtains, with respect to each of the four wheels 4, achange speed V_(ij) of a corresponding one of the four body heights.Then, at Steps S192 and S193, the ECU 200 selects, from the thusobtained four change speed values V, the smallest value V_(min) and thesecond smallest value V_(midL) and, at Steps S194 and S195, the ECU 200judges whether an absolute value ΔV of a difference (V_(min)−V_(midL))of the smallest value V_(min) and the second smallest value V_(midL) isgreater than an abnormality judging threshold value, ΔV_(th). If apositive judgment is made at Step S195, the control goes to Step S196 tojudge that there is a possibility that an object may be present in adirection of movement of a portion of the body 8 that is opposed to thewheel 4 corresponding to the smallest value dG_(min). On the other hand,if a negative judgment is made at Step S195, the control goes to StepS197 to judge that all the four speed values V corresponding to the fourwheels 4 are normal, i.e., that there is no possibility that an objectmay be present. Since the smallest value V_(min) is normal, it can bejudged that all the speed values V are normal.

In another modified form of Embodiment 5, the respective changeacceleration values G_(ij) of the four body heights are used by thesuspension ECU 200, in place of the respective change speed valuesV_(ij) of the four body heights, according to the flow chart shown inFIG. 9B.

In yet another modified form of Embodiment 5, the respective changeacceleration values G_(ij) of the four body heights are used by thesuspension ECU 200, in place of the respective change speed valuesV_(ij) of the four body heights, according to the flow chart shown inFIG. 9C.

In another modified form of Embodiment 5, at Step S8, the suspension ECU200 may judge whether the greatest one, G_(max), of the four changeaccelerations G is equal to, or greater than, a normality judgingthreshold value, G₂, (i.e., G_(max)≧G₂), and whether the changeacceleration G_(ij) of each of the four body heights is equal to, orsmaller than, an abnormality judging threshold value, G₁, (i.e.,G_(ij)≦G₁).

When the greatest acceleration G_(max) is not smaller than the normalityjudging threshold value G₂, then it can be judged that the currentbody-height controlling operation is being normally performed. Thenormality judging threshold value G₂ is a value around 0, and theabnormality acceleration judging threshold value G₁ is a value that issmaller than the value G₂ and indicates that the body 8 may have beencontacted with an object.

FIG. 10 shows a flow chart representing an object-presence-possibilitydetecting routine that is implemented at Step S8 in the above modifiedform.

At Step S111, the suspension ECU 200 obtains, with respect to each ofthe four wheels 4 (4FL, 4FR, 4RL, 4RR), a change acceleration G_(ij)(i=F, R, j=L, R) of a corresponding one of the four body heights. Then,at Step S112, the ECU 200 judges whether the greatest one G_(max) of thefour change accelerations G is equal to, or greater than the normalityjudging threshold value G₂. If a positive judgment is made at Step S112,the control goes to Step S113 through S117 to judge, with respect toeach of the four wheels 4, whether the change acceleration G_(ij) isequal to, or smaller than, the abnormality judging threshold value G₁.That is, when it is judged that the greatest change acceleration G_(max)is normal, the ECU 200 judges, with respect to each of the four wheels4, whether there is a possibility that an object may be present.

More specifically described, at Step S113, a counter, n, counts one,i.e., n=1 (n is 1, 2, 3, or 4: 1 is FL; 2 is FR; 3 is RL; and 4 is RR).Then, at Step S114, the ECU 200 judges whether the change accelerationG_(n) of the body height corresponding to the wheel n is equal to, orsmaller than, the abnormality judging threshold value G₁ (G_(n)≦G₁). Ifthe change acceleration G_(n) is not greater than the threshold valueG₁, then it is judged at Step S115 that the change of the body heightcorresponding to the wheel n is abnormal. Each time a judgment is madeat Step S114, the counter n is incremented by one at Step S116.Meanwhile, if the counter n counts 5, a positive judgment is made atStep S117, indicating that all the change accelerations G have beenchecked.

On the other hand, if it is judged at Step S112 that the greatest changeacceleration G_(max) is smaller than the normality judging thresholdvalue G₂, the control goes to Step S118 to judge that all the respectivechanges of the four body heights are abnormal.

In the modified form shown in FIG. 10, the ECU 200 judges, with respectto each of the four wheels 4, whether there is a possibility that anobject may be present in a direction of movement of a portion of thebody 8 that corresponds to the each wheel 4.

Thus, based on the respective changes of the four body heights, i.e.,the respective changes of respective relative-positional relationshipsbetween the body 8 and the four wheels 4, the suspension ECU 200 candetect, with respect to each of the four wheels 4, whether there is apossibility that an object may be present in a direction of movement ofa portion of the body 8 that corresponds to the each wheel 4. In thiscase, the ECU 200 may stop the control of only the body height orheights whose change or changes has or have been judged as beingabnormal. However, if the control of only a portion of the four bodyheights, i.e., one, two, or three (but not four) body heights is stoppedand the control of the remaining portion of the four body heights iscontinued, the one, two, or three body heights may be adverselyinfluenced by the control of the remaining portion of the body heights.Hence, in the case where with respect to each of a plurality of wheels4, it is judged that there is a possibility that an object may bepresent in a direction of movement of a portion of the body 8 thatcorresponds to the each wheel 4, the ECU 200 may stop, based on arelative-positional relationship between the plurality of wheels 4,either the control of all the body heights corresponding to the fourwheels 4, or the control of only the body heights corresponding to theplurality of wheels 4.

FIG. 11 shows a flow chart representing a body-movement restrainingroutine that is implemented at Step S17 in the above modified form. AtStep S121, the suspension ECU 200 judges whether the respective changesof at least three body heights out of the four body heights have beenjudged as being abnormal at, e.g., Step S115 or S118 of FIG. 10. If apositive judgment is made at Step S121, the control goes to Step S122 tostop the control of all the four body heights corresponding to the fourwheels 4, respectively.

On the other hand, if a negative judgment is made at Step S121, i.e., ifthe change or respective changes of one or two body heights has or havebeen judged as being abnormal at, e.g., Step S15, then the control goesto Step S123 to judge whether the respective changes of the two bodyheights corresponding to the front left and right wheels 4FL, 4FR havebeen judged as being abnormal. If a positive judgment is made at StepS123, the control goes to Step S125 to stop the control of the two bodyheights corresponding to the front left and right wheels 4FL, 4FR, andcontinues the control of the two body heights corresponding to the rearleft and right wheels 4RL, 4RR. Consequently, a front portion of thebody 8 that is located in front of the two portions of the body 8 thatcorrespond to the two front wheels 4FL, 4FR is moved in a directionopposite to the direction in which the two portions of the body 8 thatcorrespond to the two rear wheels 4RL, 4RR are moved, that is, thedirection with respect which it has been detected that there is apossibility that an object may be present. Thus, the two portions of thebody 8 that correspond to the two front wheels 4FL, 4FR can beeffectively prevented from butting against the object.

On the other hand, if a negative judgment is made at Step S123, then thecontrol goes to Step S124 to judge whether the respective changes of thetwo body heights corresponding to the rear left and right wheels 4RL,4RR have been judged as being abnormal. If a positive judgment is madeat Step S124, the control goes to Step S126 to stop the control of thetwo body heights corresponding to the rear left and right wheels 4RL,4RR, and continues the control of the two body heights corresponding tothe front left and right wheels 4FL, 4FR. Consequently, a rear portionof the body 8 that is located in rear of the two portions of the body 8that correspond to the two rear wheels 4RL, 4RR is moved in a directionopposite to the direction in which the two portions of the body 8 thatcorrespond to the two front wheels 4FL, 4FR are moved, that is, thedirection with respect which it has been detected that there is apossibility that an object may be present. Thus, the two portions of thebody 8 that correspond to the two rear wheels 4RL, 4RR can beeffectively prevented from bumping against the object.

On the other hand, if a negative judgment is made at Step S124, then thecontrol goes to Step S127 to judge whether the respective changes of thetwo body heights corresponding to the front and rear right wheels 4FR,4RR have been judged as being abnormal. If a positive judgment is madeat Step S127, the control goes to Step S129 to stop the control of thetwo body heights corresponding to the front and rear right wheels 4FR,4RR, and continues the control of the two body heights corresponding tothe front and rear left wheels 4FL, 4RL.

On the other hand, if a negative judgment is made at Step S127, then thecontrol goes to Step S128 to judge whether the respective changes of thetwo body heights corresponding to the front and rear left wheels 4FL,4RL have been judged as being abnormal. If a positive judgment is madeat Step S128, the control goes to Step S130 to stop the control of thetwo body heights corresponding to the front and rear left wheels 4FL,4RL, and continues the control of the two body heights corresponding tothe front and rear right wheels 4FR, 4RR.

If a negative judgment is made at each of Steps S123, S124, S127, andS128, that is, if the respective changes of the two body heightscorresponding to the two wheels 4 that are located on a diagonal line ofthe body 8 have been judged as being abnormal, or if the change of onlyone of the four body heights has been judged as being abnormal, then thecontrol goes to Step S122 to stop the control of all the four bodyheights.

Thus, in the modified form shown in FIG. 11, the suspension ECU 200stops, when the respective changes of the two body heights have beenjudged as being abnormal, either the control of all the four heights orthe control of only those two body heights. Thus, the ECU 200 canprevent a useless consumption of energy.

However, if the change of only one of the four body heights has beenjudged as being abnormal, and the one body height corresponds to one ofthe two front wheels 4FL, 4FR, the ECU 200 may implement Step S125; andif the change of only one of the four body heights has been judged asbeing abnormal, and the one body height corresponds to one of the tworear wheels 4RL, 4RR, the ECU 200 may implement Step S126.

In Embodiment 5, if each of the above-described predetermined conditionsis met once, then the ECU 200 detects that there is a possibility thatan object may be present. However, the ECU 200 may be modified such thatif each of the above-described predetermined conditions is met aplurality of times, e.g., if the each condition is continuously met fora predetermined time duration, then the ECU 200 detects the possibilityof presence of object.

In Embodiment 5, the body-height sensors 220 and a portion of thesuspension ECU 200 that stores and implements Step S111 cooperate witheach other to constitute a plurality of individual height-changedetecting portions; and a portion of the suspension ECU 200 that storesand implements Steps S112 through S118 constitutes a plurality ofindividual height-change-dependent possibility detecting portions. Inaddition, a portion of the suspension ECU 200 that stores and implementsSteps S125, S126, S129, and S130 constitutes a partly stopping portion;and a portion of the suspension ECU 200 that stores and implements StepS122 constitutes a fully stopping portion.

Embodiment 6

In Embodiment 6, too, a height controlling operation is performed suchthat all the individual control valves 110 are controlled in a samemanner. Therefore, the suspension ECU 200 can detect the possibility ofpresence of object, based on a change of a posture of the vehicle's body8. More specifically described, at Step S8, the ECU 200 judges whether aposture of the body 8 after a height controlling operation is startedhas changed from a posture of the body 8 when the operation is started.If a positive judgment is made at Step S8, the ECU 200 judges, at StepS9, that there is a possibility that an object may be present. Forexample, in the case where the body 8 takes a substantially horizontalposture (θ₀≈0) immediately before a height controlling operation isstarted, if the body 8 takes, after the height controlling operation isstarted, such a tilting posture that an angle, θ₁, of inclination of theposture with respect to a longitudinal or widthwise direction of thebody 8 (or the vehicle) is greater than a predetermined angle, θ_(s),then the ECU 200 judges that there is a possibility that an object maybe present. The inclination angle θ₁ of the posture of the body 8 isdetermined by the ECU 200 based on the respective body heights detectedby the four body-height sensors 220. In the present embodiment, aninclination angle of one of a forward tilting and a rearward tilting isexpressed as a positive angle, and an inclination angle of the othertiling is expressed as a negative angle. At Step S9, a positive judgmentis made when the following condition is met:

θ₀=0 and |θ₁|≧θ_(s)

FIG. 12 shows an object-presence-possibility detecting routine that isimplemented at Step S8. First, at Step S151, the suspension ECU 200judges whether an initial-angle determination flag is set at an ON statethereof. Initially, a negative judgment is made at Step S151, and thecontrol of the ECU 200 goes to Step S152 to determine an initialinclination angle θ₀ of the body 8, and then to Step S153 to set theinitial-angle determination flag to the ON state. In many cases, theinitial inclination angle θ₀ is substantially zero, i.e., the posture ofthe body 8 is substantially horizontal.

When Step S151 is implemented again, the initial-angle determinationflag has been set at the ON state and accordingly a positive judgment ismade at Step S151. Thus, the control goes to Step S154 to determine acurrent inclination angle θ₁ of the body 8. Step S154 is followed byStep S155 to obtain an absolute value of an amount of change of thecurrent inclination angle θ₁ from the initial inclination angle θ₀ andjudge whether the thus obtained absolute value is equal to, or greaterthan, the predetermined angle θ_(s) as a reference value. If a negativejudgment is made at Step S155, the control goes to Step S156 to judgethat there is no possibility that an object may be present. On the otherhand, if a positive judgment is made at Step S155, the control goes toStep S157 to judge that there is a possibility that an object may bepresent.

In Embodiment 6, a portion of the suspension ECU 200 that stores andimplements Steps S151 through S157 constitutes aposture-change-dependent possibility detecting portion.

In place of the above-described change amount of the inclination angleθ, a change acceleration of the angle θ, or a differentiated value ofthe change acceleration of the angle θ may be used to detect thepossibility of presence of object. In addition, the current inclinationangle θ₁ itself may be used to detect the possibility. For example, inthe case where it is known, in advance, that a posture of the body 8when a height controlling operation is started is substantiallyhorizontal, the ECU 200 can judge that there is the possibility, if thecurrent inclination angle θ₁ of the body 8 is greater than a referenceangle.

In addition, the inclination angle θ may be replaced with a difference(i.e., a relative change) of each one of the four body heights from eachof the other body heights.

For example, in the case where one of the four body heightssignificantly largely differs from each of the other body heights, theECU 200 can judge that there is a possibility that an object may bepresent in a direction of movement of a portion of the body 8 thatcorresponds to the wheel corresponding to the each body height.

More specifically described, for example, when a height controllingoperation is performed to decrease the four body heights in a samemanner, the ECU 200 can judge, at Steps S8 and S9, that there is apossibility that an object may be present, if a value obtained bysubtracting, from the greatest value, H_(max), of the four body heights,the second greatest body height, H_(midH), is equal to, or greater than,a predetermined abnormality judging threshold value, ΔHs(H_(max)−H_(midH)≧ΔH_(s)). The abnormality judging threshold valueΔH_(s) may be determined based on the second greatest body heightH_(midH) (ΔH_(s)=N·H_(midH); N is a coefficient).

Similarly, when a height controlling operation is performed to increasethe four body heights in a same manner, the ECU 200 can judge, at StepsS8 and S9, that there is a possibility that an object may be present, ifa value obtained by subtracting the smallest value, H_(min), of the fourbody heights from the second smallest body height, H_(midL), is equalto, or greater than, a predetermined abnormality judging thresholdvalue, ΔHs (H_(midL)−H_(min)≧ΔH_(s)). The abnormality judging thresholdvalue ΔH_(s) may be either a default value or a value determined basedon the smallest body height H_(min) (ΔH_(s)=N·H_(min); N is acoefficient).

Embodiment 7

A speed of change of each of the four body heights depends on a pressureof the working liquid in the liquid chamber 16 of a corresponding one ofthe four suspension cylinders 10 and a temperature of the workingliquid. In the case where all the four body heights are controlled in asame manner in which, e.g. the four individual control valves 110 areopened by a same degree, the working liquid flows faster when thetemperature of the liquid is high than when the temperature of theliquid is low. In addition, when the four body heights are increased,the working liquid flows faster when a difference of the pressure of theworking liquid in the liquid chamber 16 of a corresponding one of thefour suspension cylinders 10 and the pressure of the liquid in thepressure storage accumulator 86 (or the pumping device 84) is great,than when the pressure difference is small. That is, when the pressuredifference is great, a change of the pressure of the working liquid ineach suspension cylinder 10 is greater than a change of the pressure ofthe working liquid outputted from the pumping device 84 or stored by thepressure storage accumulator 86. Thus, it can be speculated that theabove-described pressure difference depends on the pressure of theworking liquid in each suspension cylinder 10. Similarly, when the fourbody heights are decreased, the working liquid flows faster when adifference of the pressure of the working liquid in the liquid chamber16 of a corresponding one of the four suspension cylinders 10 and thepressure of the liquid in the reservoir 78 is great than when thepressure difference is small. In the latter case, since the pressure ofthe liquid in the reservoir 78 is kept substantially equal to anatmospheric pressure, the above-described pressure difference depends onthe pressure of the working liquid in each suspension cylinder 10.

Hence, in the present embodiment, when the four body heights aredecreased, the ECU 200 judges, at Step S8, whether a value, (SV-V),obtained by subtracting an actual height-decrease speed, V, from astandard height-decrease speed, SV, estimated based on a pressure of theworking liquid in the liquid chamber 16 of a corresponding one of thefour suspension cylinders 10 and a temperature of the liquid is greaterthan an abnormality judging threshold value, ΔVth. If the followingexpression, SV>V, is met, then the ECU 200 judges that there is apossibility that an object may be present.

The standard height-decrease speed SV is determined by the ECU 200according to a table 300 represented by a map shown in FIG. 13. Thus, inthe present embodiment, the ECU 200 detects the possibility of presenceof object with respect to each of the four body heights, i.e., each ofthe four wheels 4.

FIG. 14 shows a flow chart representing an object-presence-possibilitydetecting routine that is implemented at Step S8 in this embodiment.

First, at Step S171, the ECU 200 obtains a temperature of the workingliquid, detected by the working liquid temperature sensor 232. At StepS172, a counter, n, counts one (n=1). Then, at Step S173, the ECU 200obtains a pressure, P_(n), of the working liquid in the liquid chamber16 of each of the four suspension cylinders 10 _(n) (n=1, 2, 3, 4; 1=FL,2=FR, 3=R L, 4=RR), and additionally obtains, at Step S174, a standardchange speed SV_(n) according to the table 300. Subsequently, at StepS175, the ECU 200 obtains an actual change speed, V*_(n), from the bodyheight values repetitively detected by a corresponding one of thebody-height sensors 220. At Step S176, the ECU 200 judges whether anabsolute value of a value, ΔV (=SV_(n)−V*_(n)), obtained by subtractingthe actual change speed V*_(n) from the standard change speed SV_(n) isgreater than an abnormality judging threshold value ΔVth. If a positivejudgment is made at Step S176, then the control of the ECU 200 goes toStep S177 to make a judgment that the change of the body heightcorresponding to the suspension cylinder 10 _(n) is abnormal. On theother hand, a negative judgment made at Step S176 indicates that thechange of the body height is normal. Thus, the control skips Step S177and directly goes to Step S178 where the number counted by the counter nis incremented by one. When the respective changes of the four bodyheights have all been checked, a positive judgment is made at Step S179.

In Embodiment 7, a portion of the suspension ECU 200 that stores andimplements Steps S171 through S179 constitutes a change-speed-dependentpossibility detecting portion.

However, the suspension ECU 200 may determine, with respect to each ofthe four body heights, a difference of an actual height-decrease speedof the each body height and a standard height-decrease speed determinedtherefor as described above, and judge whether the body heightcorresponding to the greatest one, ΔV_(max), of the thus determined fourdifferences is abnormal by, e.g., comparing the greatest difference withan abnormality judging threshold.

In addition, like in the above-described embodiments, the suspension ECU200 may judge, if a difference of the greatest difference ΔV_(max) andthe second greatest difference, ΔV_(midH), of the above-described fourdifferences is greater than an abnormality judging threshold, ΔV_(tha)(i.e., ΔV_(max)−ΔV_(midH)>ΔV_(tha)), that the body height correspondingto the greatest difference ΔV_(max) is abnormal, or may judge, if adifference of the second greatest difference ΔV_(midH) and the secondsmallest difference, ΔV_(midL), of the four differences is greater thanan abnormality judging threshold, ΔV_(tha) (i.e.,ΔV_(midH)−ΔV_(midL)>ΔV_(tha)), that the two body heights correspondingto the greatest difference ΔV_(max) and the second greatest differenceΔV_(midH) are abnormal.

The above description can apply to a case where a height controllingoperation is performed to increase the four body heights. In this case,as indicated by a map 302 shown in FIG. 15, the change speed V of eachof the body heights is lower when the pressure of the working liquid ina corresponding one of the four suspension cylinders 10 is high thanwhen it is low, because a difference of it and the liquid pressure inthe pressure storage accumulator 86 is smaller when it is high than whenit is low.

Embodiment 8

In Embodiment 8, the suspension ECU 200 uses a predetermined timeduration within which a height controlling operation should be completedif the operation is normally performed, i.e., if no object is present ina direction of movement of the vehicle's body 8, and judges, at Step S8,whether the height controlling operation has been completed within thepredetermined time duration, i.e., whether any of the four body heightshas not reached a target body height. If a negative judgment is made atStep S8, the ECU 200 makes, at Step S9, that there is a possibility thatan object may be present in a direction of movement of a portion of thebody 8 that corresponds to the wheel 4 corresponding to that bodyheight. If a height controlling operation is not completed within apredetermined time duration within which the operation should becompleted, the ECU 200 can judge that the operation is abnormal.

In each of Embodiments 4 through 8, the suspension ECU 200 detects thepossibility of presence of object, by using the time-wise change of eachof the four body heights, i.e., one of the change speed of the each bodyheight, the differentiated value of the change acceleration of the eachbody height, the comparison of the respective time-wise changes of thefour body heights, the comparison of the actual change speed of the eachbody height and the standard change speed determined therefor, and theactual time duration needed to complete the body-height controllingoperation. However, the ECU 200 can detect the possibility of presenceof object, by using two or more of the above-described physical amountsor comparison results.

Alternatively, the suspension ECU 200 can detect the possibility ofpresence of object, based on both the judgment made in at least one ofEmbodiments 1 through 3 and the judgment made in at least one ofEmbodiments 4 through 8. For example, a) the ECU 200 may judge thatthere is a possibility that an object may be present in a direction ofmovement of the body 8, if it is judged that the time-wise change of anyof the four body heights is abnormal and that an object is present nearto the vehicle; b) Step S4 may be implemented in the manner employed inleast one of Embodiments 1 through 3, while Step S8 is implemented inthe manner employed in at least one of Embodiments 4 through 8; or c)Step S4 may be implemented in the manner employed in least one ofEmbodiments 1 through 3, while Step S8 is implemented in two manners,i.e., the manner employed in least one of Embodiments 1 through 3 andthe manner employed in at least one of Embodiments 4 through 8.

In each of the above-described embodiments, the suspension ECU 200controls, when the ignition switch 236 is in its ON state, the pumpingdevice 84 such that the pressure of the working liquid in the pressurestorage accumulator 86 falls within a predetermined pressure range.However, the ECU 200 may be modified such that also when the ignitionswitch 236 is kept in its OFF state, the ECU 200 controls the pumpingdevice 84 so that the liquid pressure in the accumulator 86 falls withina predetermined pressure range.

Alternatively, the ECU 200 may be modified such that after the ignitionswitch 236 is switched from its ON state to its OFF state, the ECU 200controls the pumping device 84 so that the liquid pressure in thepressure storage accumulator 86 is increased to a pressure not lowerthan a predetermined pressure.

For example, when the information transmitted from the portablecontroller 282 is used in decreasing the body heights, the ignitionswitch 236 is often in its OFF state. However, as described above, it isnot desirable, when the body heights are increased during a high-speedheight decreasing operation, i.e., are changed in a reversed direction,that the liquid pressure in the pressure storage accumulator 86 be lowerthan the predetermined pressure. Hence, in an embodiment shown in FIG.16, the suspension ECU 200 controls the liquid pressure in theaccumulator 86 so as to be not lower than the predetermined pressure,when the ignition switch 236 is switched from its ON state to its OFFstate.

FIG. 16 shows a pumping-device controlling program. This program isimplemented by, e.g., interception, each time a predetermined timeelapses.

First, at Step S201, the suspension ECU 200 judges whether the ignitionswitch (IG) 236 is in its ON state. If a positive judgment is made atStep S201, the control of the ECU 200 goes to Step S202 to operate thepumping device 84 so that the liquid pressure in the pressure storageaccumulator 86 is kept to the predetermined pressure range, as describedabove.

On the other hand, if a negative judgment is made at Step S201, i.e., ifthe ignition switch 236 is in its OFF state, the control goes to StepS203 to judge whether the ignition switch 236 has been switched from itsON state to the OFF state. If a positive judgment is made at Step S203,the control goes to Step S204 to read a liquid pressure, P_(ACC), in thepressure storage accumulator 86 detected by the accumulator pressuresensor 92, and then goes to Step S205 to judge whether the read liquidpressure P_(ACC) is equal to, or higher than a predetermined pressure,P_(SACC). If a negative judgment is made at Step S205, the control goesto Step S206 to open the pressure storage control valve 90 and then goesto Step S207 to operate the pumping device 84. Meanwhile, if a positivejudgment is made at Step S205, the control goes to Step S208 to closethe pressure storage control valve 90 and then goes to Step S209 to stopthe pumping device 84.

Thus, when the ignition switch 236 is switched from the ON state to theOFF state, the accumulator pressure P_(ACC) is increased to a pressurenot lower than the predetermined pressure P_(SACC). Therefore, if it isoccasionally needed to increase the body heights when a heightcontrolling operation is performed to decrease the body heights, thebody heights can be quickly increased owing the increased accumulatorpressure P_(ACC).

In the embodiment shown in FIG. 16, a portion of the suspension ECU 200that stores and implements Steps S207 and S209 constitutes apumping-device control portion.

In each of the above-described embodiments, the pump 81 is operated bybeing exclusively driven by the pump motor 82. However, the pump 81 maybe operated by being driven by the engine of the vehicle. In this case,if a negative judgment is made at Step S205, then the suspension ECU 200does not stop, at Step S207, the engine so as to be able to operate pump81. Meanwhile, if a positive judgment is made at Step S205, then the ECU200 stops, at Step S209, the engine.

Otherwise, the suspension ECU 200 may be modified such that when theaccumulator pressure P_(ACC) is lower than the predetermined pressureP_(SACC), the ECU 200 stops the current high-speed height controllingoperation, according to a height controlling program represented by aflow chart shown in FIG. 17. At Step S3, the ECU 200 judges whetherthere is a need to perform a high-speed height controlling operation,when the ignition switch 236 is in its OFF state. If a positive judgmentis made at Step S3, the control of the ECU 200 goes to Step S221 tojudge whether the accumulator pressure P_(ACC) is lower than thepredetermined pressure P_(SACC). If a negative judgment is made at StepS221, the control goes to Step S4 and the following steps, as describedabove, so as to detect whether there is a possibility that an object maybe present. If a negative judgment is made at Step S5, the control goesto Step S6 to set the high-speed height-control flag to its ON state,and then goes to Step S7 to start the high-speed height controllingoperation.

On the other hand, if a positive judgment is made at Step S221, thesuspension ECU 200 quits this routine, i.e., does not implement Step 4or any following steps. That is, the ECU 200 does not detect whetherthere is a possibility that an object may be present, or does notperform a height controlling operation. Thus, even if there may be nopossibility that an object may be present in a direction of movement ofthe body 8, the ECU 200 does not start a height controlling operation.

Therefore, the present embodiment is free of the above-indicated problemthat if it is occasionally needed to increase the body heights when ahigh-speed height controlling operation is performed to decrease thebody heights, the body heights cannot be quickly increased.

Meanwhile, the suspension ECU 200 may be modified such that at Step S3,the ECU 200 judges whether it has received, from the portable controller282, the information representing the high-speed height controllingcommand, since a positive judgment is often made at Step S3 when the ECU200 (or the communication device 280) receives the information from theportable controller 282.

In each of the above-described embodiments, the suspension ECU 200performs height controlling operations both for the purpose ofincreasing the body heights and for the purpose of decreasing the bodyheights. However, the ECU 200 may be modified to perform heightcontrolling operations not for increasing the body heights but fordecreasing the body heights.

The suspension ECU 200 may be one that can operate in the mannerdescribed with respect to at least one of Embodiments 1 through 8.

In each of the above-described embodiments, the height controllingapparatus 74 uses the working liquid. However, the height controllingapparatus may be one that uses air as another sort of working fluid. Inaddition, the height controlling apparatus may be employed by any othersort of suspension system than the above-described suspension system.For example, the suspension system may be one that does not include thecenter cylinder 52, the low-pressure accumulators 26, or thehigh-pressure accumulators 24.

In each of the above-described embodiments, the change of each of thefour body heights is detected by a corresponding one of the fourbody-height sensors 220. However, the body-height sensors 220 may bereplaced with vertical-direction acceleration sensors that detect, inthe vertical direction, respective accelerations of four portions of thevehicle's body 8 that are opposed to the four wheels 4.

While the present invention has been described in detail in itsembodiments, it is to be understood that the present invention is notlimited to the details of those embodiments and may be embodied withvarious changes and improvements, such as those described in SUMMARY OFTHE INVENTION, which may occur to a person skilled in the art.

1. A height controlling apparatus for controlling a plurality of actualheights each of which is defined as a relative position of (a) acorresponding one of a plurality of portions of a body of a vehicle and(b) a corresponding one of a plurality of wheels of the vehicle, theapparatus comprising: a plurality of height controlling actuators eachof which corresponds to at least one of the plurality of wheels andchanges at least one of the plurality of actual heights respectivelycorresponding to the plurality of wheels; and an actuator control devicewhich controls the plurality of height controlling actuators so that theplurality of actual heights respectively approach a plurality of targetheights, wherein the actuator control device includes a same-manneractuator control portion which controls, in a same manner, at least twoheight controlling actuators of the plurality of height controllingactuators so as to respectively change at least two actual heights ofthe plurality of actual heights, a possibility detecting device whichdetects whether there is a possibility that an object may be present ina direction in which at least one of the plurality of portions of thebody is moved to change at least one of the plurality of actual heights,wherein the possibility detecting device includes a firstrelative-change-dependent possibility detecting portion which detects,in a state in which the vehicle is in a stopped state thereof and thesame-manner actuator control portion controls, in the same manner, saidat least two height controlling actuators so that said at least twoactual heights respectively approach at least two target heights of theplurality of target heights, whether there is said possibility, based ona relative change of said at least two actual heights changed by said atleast two height controlling actuators, and a movement restrainingportion which controls, when the first relative-change-dependentpossibility detecting portion detects that there is said possibility, atleast one height controlling actuator of said at least two controllingactuators to restrain a movement of said at least one portion of thebody in said direction.
 2. The height controlling apparatus according toclaim 1, wherein the possibility detecting device further includes anear-object detecting portion which detects whether there is the objectnear to the vehicle, and wherein the movement restraining portionincludes a near-object-detection-dependent actuator control portionwhich controls, when the near-object detecting portion detects thatthere is the object near to the vehicle, said at least one heightcontrolling actuator to restrain the movement of said at least oneportion of the body in said direction.
 3. The height controllingapparatus according to claim 2, wherein the near-object detectingportion includes an object-in-area detecting portion which detectswhether there is the object in at least one area predetermined withrespect to the vehicle.
 4. The height controlling apparatus according toclaim 3, wherein the object-in-area detecting portion includes arelative-positional-relationship detecting portion which detects arelative-positional relationship between the body and the object presentin said at least one area.
 5. The height controlling apparatus accordingto claim 3, wherein the object-in-area detecting portion includes anoperation detecting portion which detects whether an operation is beingperformed by an operator with respect to the vehicle.
 6. The heightcontrolling apparatus according to claim 3, wherein the object-in-areadetecting portion includes a door-state detecting portion which detectsat least one of (a) whether at least one door of the vehicle is openedand (b) whether at least one door of the vehicle is closed.
 7. Theheight controlling apparatus according to claim 1, wherein thepossibility detecting device further includes a height-change-dependentpossibility detecting portion which detects whether there is saidpossibility, based on a change of said at least one actual height, andwherein the movement restraining portion includes aheight-change-dependent actuator control portion which controls, whenthe height-change-dependent possibility detecting portion detects thatthere is said possibility, said at least one height controlling actuatorto restrain the movement of said at least one portion of the body insaid direction.
 8. The height controlling apparatus according to claim7, wherein the height-change-dependent possibility detecting portionincludes a change-speed-related-amount-dependent possibility detectingportion which detects whether there is said possibility, based on aphysical amount related to a speed of change of said at least one actualheight.
 9. The height controlling apparatus according to claim 7,wherein the plurality of height controlling actuators include aplurality of fluid-flow controlling actuators each of which controls aworking fluid to flow into, and out of, at least one fluid chamber whichis provided between the body and at least one of a plurality of wheelholding devices which respectively hold the plurality of wheels, whereinthe actuator control device includes a fluid-flow control portion whichcontrols the plurality of fluid-flow controlling actuators so as torespectively change the plurality of actual heights, and wherein theheight-change-dependent possibility detecting portion includes achange-speed-dependent possibility detecting portion which detects thatthere is said possibility, when a speed of change of said at least oneactual height is lower than a reference change speed determined based onat least one of a temperature of the working fluid and a pressure of theworking fluid in said at least one fluid chamber.
 10. The heightcontrolling apparatus according to claim 1, wherein the possibilitydetecting device further includes a second relative-change-dependentpossibility detecting portion which detects whether there is saidpossibility, based on a relative change of respective physical amountsrelated to respective speeds of change of said at least two actualheights changed by said at least two height controlling actuators. 11.The height controlling apparatus according to claim 1, wherein the firstrelative-change-dependent possibility detecting portion includes alowest-change-speed-dependent possibility detecting portion whichdetects whether there is said possibility, based on a lowest changespeed of respective change speeds of said at least two actual heightschanged by said at least two height controlling actuators.
 12. Theheight controlling apparatus according to claim 10 wherein the secondrelative-change-dependent possibility detecting portion includes alowest-change-acceleration-dependent possibility detecting portion whichdetects whether there is said possibility, based on a lowest changeacceleration of respective accelerations of change of said at least twoactual heights changed by said at least two height controllingactuators.
 13. The height controlling apparatus according to claim 10,wherein the second relative-change-dependent possibility detectingportion includes a smallest-differentiated-value-dependent possibilitydetecting portion which detects whether there is said possibility, basedon a smallest differentiated value of respective differentiated valuesof respective accelerations of change of said at least two actualheights changed by said at least two height controlling actuators. 14.The height controlling apparatus according to claim 7, wherein theheight-change-dependent possibility detecting portion includes aposture-change-dependent possibility detecting portion which detectswhether there is said possibility, based on at least one of (a) a changeof a posture of the body and (b) a physical amount related to a speed ofchange of the posture.
 15. The height controlling apparatus according toclaim 1, wherein the possibility detecting device includes apossibility-degree detecting portion which detects each of a pluralityof different degrees of said possibility.
 16. The height controllingapparatus according to claim 1, wherein the movement restraining portionincludes at least one of (a) a movement-stopping control portion whichcontrols, when the possibility detecting device detects that there issaid possibility, said at least one height controlling actuator to stopthe movement of the body, and (b) a direction-reversing control portionwhich reverses, when the possibility detecting device detects that thereis said possibility, said direction of the movement of the body so thatthe body is moved in a reversed direction.
 17. The height controllingapparatus according to claim 1, wherein the movement restraining portionincludes a speed-decrease control portion which controls, when thepossibility detecting device detects that there is said possibility,said at least one height controlling actuator to decrease a speed of themovement of the body in said direction.
 18. The height controllingapparatus according to claim 1, wherein the possibility detecting deviceincludes a possibility-degree detecting portion which detects each of aplurality of different degrees of said possibility, and wherein themovement restraining portion includes a possibility-degree-dependentactuator control portion which controls said at least one heightcontrolling actuator in each of a plurality of different mannerscorresponding to the plurality of different degrees of said possibility,respectively.
 19. The height controlling apparatus according to claim 1,wherein the actuator control device includes an operation resumingportion which resumes, when at least one predetermined resumingcondition including a condition that the movement of the body in saiddirection has been stopped by said at least one height controllingactuator under control of the movement restraining portion and at leastone door of the vehicle has been changed from an opened state thereof toa closed state thereof, is met, an operation of said at least one heightcontrolling actuator so as to change said at least one actual height.20. The height controlling apparatus according to claim 1, wherein theactuator control device includes a high-speed actuator control portionwhich controls said at least one height controlling actuator to changesaid at least one actual height at a speed higher than a predeterminedheight-change speed; a low-speed actuator control portion which controlssaid at least one height controlling actuator to change said at leastone actual height at a speed not higher than the predeterminedheight-change speed; and a high-speed-control-related actuator controlportion which controls, when the high-speed actuator control portioncontrols said at least one height controlling actuator and thepossibility detecting device detects that there is said possibility,said at least one height controlling actuator to restrain the movementof the body in said direction and which does not control, when thelow-speed actuator control portion controls said at least one heightcontrolling actuator and the possibility detecting device detects thatthere is said possibility, said at least one height controlling actuatorto restrain the movement of the body in said direction.
 21. The heightcontrolling apparatus according to claim 1, wherein the possibilitydetecting device includes a plurality of individual change detectingportions which detect respective changes of the actual heights; and aplurality of individual possibility detecting portions each of whichdetects, based on the change of a corresponding one of the actualheights that is detected by a corresponding one of the individual changedetecting portions, whether there is the possibility that the object maybe present in the direction in which a corresponding one of the portionsof the body is moved to change said corresponding actual height, andwherein the movement restraining portion includes at least one of (a) apartly stopping portion which does not control, when at least oneindividual possibility detecting portion as a part of the individualpossibility detecting portions detects that there is the possibilitythat the object may be present in the direction in which a correspondingone of the portions of the body is moved, at least a corresponding oneof the height controlling actuators so as not to change a correspondingone of the actual heights, and (b) a fully stopping portion which doesnot control, when at least one individual possibility detecting portionas a part of the individual possibility detecting portions detects thatthere is the possibility that the object may be present in the directionin which a corresponding one of the portions of the body is moved, eachof the height controlling actuators so as not to change any of theactual heights.
 22. The height controlling apparatus according to claim1, wherein the actuator control device further includes an informingdevice which informs, when the same-manner actuator control portioncontrols said at least two height controlling actuators and the firstrelative-change-dependent possibility detecting portion detects thatthere is said possibility, at least one of (a) that said at least twoactual heights are controlled and (b) that there is said possibility.23. The height controlling apparatus according to claim 1, wherein theplurality of height controlling actuators include a plurality offluid-flow controlling actuators each of which controls a working fluidto flow into, and out of, at least one fluid chamber which is providedbetween the body and at least one of a plurality of wheel holdingdevices which respectively hold the plurality of wheels, wherein theapparatus further comprises: an accumulator which stores the workingfluid in a pressurized state and can supply the pressurized workingfluid to said at least one fluid chamber; a pumping device whichsupplies, to the accumulator, the working fluid in the pressurizedstate; and a pumping-device control portion which controls, after anignition switch is switched from an ON state thereof to an OFF statethereof, the pumping device so that a pressure of the working fluidstored by the accumulator is kept higher than a predetermined pressure.